diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 7db7bc4ea7..67736ea4dc 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -467,65 +467,6 @@ post:
   - func: "upload test results to s3"
 
 task_groups:
-  - name: serverless_task_group
-    setup_group_can_fail_task: true
-    setup_group_timeout_secs: 1800 # 30 minutes
-    setup_group:
-      - func: "fetch source"
-      - func: "create expansions"
-      - command: ec2.assume_role
-        params:
-          role_arn: ${aws_test_secrets_role}
-      - command: shell.exec
-        params:
-          shell: "bash"
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/setup-secrets.sh
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/create-instance.sh
-      - command: expansions.update
-        params:
-          file: serverless-expansion.yml
-    teardown_task:
-      - command: shell.exec
-        params:
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/delete-instance.sh
-      - func: "upload test results"
-    tasks:
-      - "test-serverless"
-
-  - name: serverless_next_task_group
-    setup_group_can_fail_task: true
-    setup_group_timeout_secs: 1800 # 30 minutes
-    setup_group:
-      - func: "fetch source"
-      - func: "create expansions"
-      - command: ec2.assume_role
-        params:
-          role_arn: ${aws_test_secrets_role}
-      - command: shell.exec
-        params:
-          shell: "bash"
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/setup-secrets.sh serverless_next
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/create-instance.sh
-      - command: expansions.update
-        params:
-          file: serverless-expansion.yml
-    teardown_task:
-      - command: shell.exec
-        params:
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/setup-secrets.sh serverless_next
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/delete-instance.sh
-      - func: "upload test results"
-    tasks:
-      - "test-serverless"
-
   - name: testatlas_task_group
     setup_group_can_fail_task: true
     setup_group_timeout_secs: 1800 # 30 minutes
@@ -755,26 +696,12 @@ tasks:
   - name: "test-atlas"
     commands:
       - func: "run Atlas tests"
-  - name: "test-serverless"
-    commands:
-      - func: "export FLE credentials"
-      - func: "run serverless tests"
-  - name: "test-docker"
-    commands:
-      - func: "build and test docker image"
   - name: "test-mlaunch"
     commands:
       - func: "run tests"
   - name: "driver-bench"
     commands:
       - func: "run benchmarks"
-  - name: "test-via-docker"
-    commands:
-      - func: "run tests via docker"
-  - name: "test-kerberos-integration"
-    commands:
-      - func: "export Kerberos credentials"
-      - func: "run Kerberos integration tests"
   - name: "test-kerberos"
     commands:
       - func: "run Kerberos unit tests"
@@ -782,10 +709,6 @@ tasks:
     commands:
       - func: "export FLE credentials"
       - func: "run tests"
-  - name: "test-fle-via-docker"
-    commands:
-      - func: "export FLE credentials"
-      - func: "run tests via docker"
   - name: "test-aws-auth"
     commands:
       - func: "export AWS auth credentials"
@@ -1081,15 +1004,15 @@ axes:
       - id: ubuntu2204
         display_name: "Ubuntu 22.04"
         run_on: ubuntu2204-small
+      - id: ubuntu2204-arm
+        display_name: "Ubuntu 22.04 ARM"
+        run_on: ubuntu2204-arm64-small
       - id: ubuntu2004
         display_name: "Ubuntu 20.04"
         run_on: ubuntu2004-small
-      - id: rhel8
-        display_name: "RHEL 8"
-        run_on: rhel80-small
-      - id: rhel8-arm
-        display_name: "RHEL 8 ARM64"
-        run_on: rhel82-arm64-small
+      - id: ubuntu1804
+        display_name: "Ubuntu 18.04"
+        run_on: ubuntu1804-small
 
   - id: docker-distro
     display_name: Docker Distro
@@ -1196,7 +1119,7 @@ axes:
     values:
       - id: mmapv1
         display_name: MMAPv1
-        run_on: rhel80-small
+        run_on: ubuntu1804-small
         variables:
           MMAPV1: 'true'
 
@@ -1302,7 +1225,7 @@ buildvariants:
       ruby: "ruby-3.2"
       mongodb-version: "7.0"
       topology: standalone
-    run_on: rhel80-large
+      os: ubuntu2204
     display_name: DriverBench
     tasks:
       - name: "driver-bench"
@@ -1311,9 +1234,9 @@ buildvariants:
     matrix_spec:
       auth-and-ssl: ["auth-and-ssl", "noauth-and-nossl"]
       ruby: "ruby-3.2"
-      mongodb-version: ["latest", "7.0", "6.0"]
+      mongodb-version: ["7.0", "6.0"]
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
+      os: ubuntu2204
     display_name: ${auth-and-ssl} ${ruby} db-${mongodb-version} ${topology}
     tasks:
       - name: "test-mlaunch"
@@ -1321,32 +1244,30 @@ buildvariants:
   - matrix_name: "mongo-recent"
     matrix_spec:
       ruby: ["ruby-3.2", "ruby-3.1", "jruby-9.4"]
-      mongodb-version: ["latest", "7.0", "6.0"]
+      mongodb-version: ["7.0", "6.0"]
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: ['rhel8']
-      # There is no latest for ubuntu2204, so we can't test it here.
-      # os: ['rhel8', 'ubuntu2204']
-    display_name: "${mongodb-version} ${os} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} ${os} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
   - matrix_name: "mongo-recent-arm"
     matrix_spec:
       ruby: "ruby-3.2"
-      mongodb-version: ["latest", "7.0", "6.0"]
+      mongodb-version: ["7.0", "6.0"]
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: 'rhel8-arm'
-    display_name: "${mongodb-version} ${os} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204-arm
+    display_name: "${mongodb-version} ${os} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
   - matrix_name: "mongo-5.x"
     matrix_spec:
       ruby: ["ruby-3.2", "ruby-2.7", "jruby-9.4"]
-      mongodb-version: ['5.3', '5.0']
+      mongodb-version: '5.0'
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu1804
+    display_name: "${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -1355,8 +1276,8 @@ buildvariants:
       ruby: ["ruby-3.0", "ruby-2.7"]
       mongodb-version: ['4.4', '4.2', '4.0']
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu1804
+    display_name: "${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -1365,8 +1286,8 @@ buildvariants:
       ruby: "ruby-2.7"
       mongodb-version: ['3.6']
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu1804
+    display_name: "${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -1376,19 +1297,19 @@ buildvariants:
       mongodb-version: "7.0"
       topology: load-balanced
       single-mongos: single-mongos
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} single-lb ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} ${topology} single-lb ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
-  - matrix_name: "mongo-5.0-api-version"
+  - matrix_name: "mongo-api-version"
     matrix_spec:
       ruby: "ruby-3.2"
-      mongodb-version: '5.0'
+      mongodb-version: '7.0'
       topology: standalone
       api-version-required: yes
-      os: rhel8
-    display_name: "${mongodb-version} api-version-required ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} api-version-required ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -1398,8 +1319,8 @@ buildvariants:
       mongodb-version: "7.0"
       topology: "sharded-cluster"
       single-mongos: single-mongos
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} single-mongos ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} ${topology} single-mongos ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -1409,7 +1330,7 @@ buildvariants:
       ruby: "ruby-3.2"
       mongodb-version: "7.0"
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${retry-reads} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1420,7 +1341,7 @@ buildvariants:
       ruby: "ruby-3.2"
       mongodb-version: "7.0"
       topology: [replica-set, sharded-cluster]
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${retry-writes} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1431,7 +1352,7 @@ buildvariants:
       mongodb-version: ['3.6', '4.0']
       topology: ["standalone", "replica-set", "sharded-cluster"]
       storage-engine: mmapv1
-      os: rhel8
+      os: ubuntu1804
     display_name: "${mongodb-version} ${topology} mmapv1 ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1442,7 +1363,7 @@ buildvariants:
       ruby: "ruby-3.2"
       mongodb-version: "7.0"
       topology: '*'
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${lint} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1453,7 +1374,7 @@ buildvariants:
       ruby: "ruby-3.2"
       mongodb-version: "7.0"
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} fork ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1464,7 +1385,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7", "jruby-9.4", "jruby-9.3"]
       mongodb-version: "7.0"
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
+      os: ubuntu2004
     display_name: "${mongodb-version} ${topology} solo ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1475,7 +1396,7 @@ buildvariants:
       ruby: ["ruby-2.7"]
       mongodb-version: ['4.2', '4.0', '3.6']
       topology: replica-set
-      os: rhel8
+      os: ubuntu1804
     display_name: "${mongodb-version} ${topology} stress ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1484,9 +1405,9 @@ buildvariants:
     matrix_spec:
       stress: on
       ruby: "ruby-3.2"
-      mongodb-version: ["6.0", "5.3"]
+      mongodb-version: ["6.0", "5.0"]
       topology: replica-set
-      os: rhel8
+      os: ubuntu2004
     display_name: "${mongodb-version} ${topology} stress ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1495,14 +1416,9 @@ buildvariants:
     matrix_spec:
       auth-and-ssl: "x509"
       ruby: "ruby-3.2"
-      # needs the latest_5x_mdb because run-tests.sh uses `mongo` to configure
-      # the server for certain auth mechanisms. Once run-tests.sh is made smart
-      # enough to install mongosh, and then use either mongo or mongosh
-      # (depending on server version and what's available), we can bump this to
-      # the latest stable db version.
-      mongodb-version: "5.3"
+      mongodb-version: "7.0"
       topology: standalone
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1513,7 +1429,7 @@ buildvariants:
       ruby: jruby-9.4
       mongodb-version: "7.0"
       topology: ["standalone", "replica-set", "sharded-cluster"]
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1525,7 +1441,7 @@ buildvariants:
       mongodb-version: "7.0"
       topology: "replica-set"
       compressor: 'zlib'
-      os: rhel8
+      os: ubuntu2004
     display_name: "${compressor} ${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1537,7 +1453,7 @@ buildvariants:
       mongodb-version: "7.0"
       topology: "replica-set"
       compressor: 'snappy'
-      os: rhel8
+      os: ubuntu2004
     display_name: "${compressor} ${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1553,7 +1469,7 @@ buildvariants:
       mongodb-version: "7.0"
       topology: "replica-set"
       compressor: 'zstd'
-      os: rhel8
+      os: ubuntu2004
     display_name: "${compressor} ${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1564,7 +1480,7 @@ buildvariants:
       mongodb-version: "7.0"
       topology: replica-set
       as: as
-      os: rhel8
+      os: ubuntu2004
     display_name: "AS ${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -1575,50 +1491,29 @@ buildvariants:
       mongodb-version: "7.0"
       topology: replica-set
       bson: "*"
-      os: rhel8
+      os: ubuntu2004
     display_name: "bson-${bson} ${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
-  # kerberos integration tests are broken (RUBY-3266)
-  # - matrix_name: "kerberos-integration"
-  #   matrix_spec:
-  #     ruby: ["ruby-3.2", "ruby-2.7", "jruby-9.4"]
-  #     os: rhel8
-  #   display_name: "Kerberos integration ${os} ${ruby}"
-  #   tasks:
-  #     - name: "test-kerberos-integration"
-
   - matrix_name: "kerberos-unit"
     matrix_spec:
       ruby: "ruby-3.2"
       mongodb-version: "7.0"
       topology: standalone
-      os: rhel8
+      os: ubuntu2204
       auth-and-ssl: kerberos
     display_name: "Kerberos Tests"
     tasks:
       - name: "test-kerberos"
 
-  - matrix_name: "fle-latest"
-    matrix_spec:
-      auth-and-ssl: "noauth-and-nossl"
-      ruby: "ruby-3.2"
-      topology: [replica-set, sharded-cluster]
-      mongodb-version: [ 'latest', '7.0' ]
-      os: rhel8
-      fle: helper
-    display_name: "FLE: ${mongodb-version} ${topology} ${ruby}"
-    tasks:
-      - name: "test-fle"
-
   - matrix_name: "fle"
     matrix_spec:
       auth-and-ssl: "noauth-and-nossl"
-      ruby: ["ruby-3.2", "ruby-2.7"]
+      ruby: "ruby-3.2"
       topology: [replica-set, sharded-cluster]
-      mongodb-version: [ '6.0', '4.4', '4.2', '4.0' ]
-      os: rhel8
+      mongodb-version: [ '6.0', '7.0' ]
+      os: ubuntu2204
       fle: helper
     display_name: "FLE: ${mongodb-version} ${topology} ${ruby}"
     tasks:
@@ -1636,7 +1531,7 @@ buildvariants:
       # enough to install mongosh, and then use either mongo or mongosh
       # (depending on server version and what's available), we can bump this to
       # the latest stable db version.
-      mongodb-version: "5.3"
+      mongodb-version: "5.0"
       os: ubuntu2004
     display_name: "AWS ${auth-and-ssl} ${mongodb-version} ${ruby}"
     tasks:
@@ -1649,7 +1544,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP verifier: ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1662,7 +1557,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
       auth-and-ssl: noauth-and-ssl
     display_name: "OCSP integration - must staple: ${mongodb-version} ${ruby}"
     tasks:
@@ -1675,7 +1570,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
       auth-and-ssl: noauth-and-ssl
     display_name: "OCSP integration - unknown: ${mongodb-version} ${ruby}"
     tasks:
@@ -1691,7 +1586,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1705,7 +1600,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1719,7 +1614,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1733,7 +1628,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1747,7 +1642,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1761,7 +1656,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1775,7 +1670,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1789,7 +1684,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1803,7 +1698,7 @@ buildvariants:
       ruby: ["ruby-3.2", "ruby-2.7"]
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1823,7 +1718,7 @@ buildvariants:
       ruby: jruby-9.4
       topology: standalone
       mongodb-version: "7.0"
-      os: rhel8
+      os: ubuntu2204
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -1833,7 +1728,7 @@ buildvariants:
       ruby: "ruby-3.2"
       fle: helper
       topology: standalone
-      os: rhel8
+      os: ubuntu2204
       mongodb-version: "7.0"
     display_name: "GCP KMS"
     tasks:
@@ -1855,7 +1750,7 @@ buildvariants:
   - matrix_name: atlas-full
     matrix_spec:
       ruby: "ruby-3.2"
-      os: rhel8
+      os: ubuntu2204
     display_name: "Atlas (Full)"
     tasks:
       - name: testatlas_full_task_group
@@ -1863,37 +1758,14 @@ buildvariants:
   - matrix_name: "atlas"
     matrix_spec:
       ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7", "jruby-9.4", "jruby-9.3"]
-      os: rhel8
+      os: ubuntu2004
     display_name: "Atlas tests ${ruby}"
     tasks:
        - name: testatlas_task_group
 
-# Commented out, pending RUBY-3414
-#  - matrix_name: "serverless"
-#    matrix_spec:
-#      # https://jira.mongodb.org/browse/RUBY-3217
-#      # ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7", "jruby-9.4", "jruby-9.3"]
-#      ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7"]
-#      fle: path
-#      os: rhel8
-#    display_name: "Atlas serverless ${ruby}"
-#    tasks:
-#       - name: serverless_task_group
-#
-#  - matrix_name: "serverless-next"
-#    matrix_spec:
-#      # https://jira.mongodb.org/browse/RUBY-3217
-#      # ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7", "jruby-9.4", "jruby-9.3"]
-#      ruby: ["ruby-3.2", "ruby-3.1", "ruby-3.0", "ruby-2.7"]
-#      fle: path
-#      os: rhel8
-#    display_name: "Atlas serverless-next ${ruby}"
-#    tasks:
-#       - name: serverless_next_task_group
-
   - matrix_name: "aws-lambda"
     matrix_spec:
-      ruby: "ruby-3.2"
+      ruby: 'ruby-3.2'
       os: ubuntu2204
     display_name: "AWS Lambda"
     tasks:
diff --git a/.evergreen/config/axes.yml.erb b/.evergreen/config/axes.yml.erb
index c433cf9c22..4b2da7ab10 100644
--- a/.evergreen/config/axes.yml.erb
+++ b/.evergreen/config/axes.yml.erb
@@ -184,15 +184,15 @@ axes:
       - id: ubuntu2204
         display_name: "Ubuntu 22.04"
         run_on: ubuntu2204-small
+      - id: ubuntu2204-arm
+        display_name: "Ubuntu 22.04 ARM"
+        run_on: ubuntu2204-arm64-small
       - id: ubuntu2004
         display_name: "Ubuntu 20.04"
         run_on: ubuntu2004-small
-      - id: rhel8
-        display_name: "RHEL 8"
-        run_on: rhel80-small
-      - id: rhel8-arm
-        display_name: "RHEL 8 ARM64"
-        run_on: rhel82-arm64-small
+      - id: ubuntu1804
+        display_name: "Ubuntu 18.04"
+        run_on: ubuntu1804-small
 
   - id: docker-distro
     display_name: Docker Distro
@@ -297,7 +297,7 @@ axes:
     values:
       - id: mmapv1
         display_name: MMAPv1
-        run_on: rhel80-small
+        run_on: ubuntu1804-small
         variables:
           MMAPV1: 'true'
 
diff --git a/.evergreen/config/common.yml.erb b/.evergreen/config/common.yml.erb
index cacba6b5aa..19cddacaca 100644
--- a/.evergreen/config/common.yml.erb
+++ b/.evergreen/config/common.yml.erb
@@ -464,65 +464,6 @@ post:
   - func: "upload test results to s3"
 
 task_groups:
-  - name: serverless_task_group
-    setup_group_can_fail_task: true
-    setup_group_timeout_secs: 1800 # 30 minutes
-    setup_group:
-      - func: "fetch source"
-      - func: "create expansions"
-      - command: ec2.assume_role
-        params:
-          role_arn: ${aws_test_secrets_role}
-      - command: shell.exec
-        params:
-          shell: "bash"
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/setup-secrets.sh
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/create-instance.sh
-      - command: expansions.update
-        params:
-          file: serverless-expansion.yml
-    teardown_task:
-      - command: shell.exec
-        params:
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/delete-instance.sh
-      - func: "upload test results"
-    tasks:
-      - "test-serverless"
-
-  - name: serverless_next_task_group
-    setup_group_can_fail_task: true
-    setup_group_timeout_secs: 1800 # 30 minutes
-    setup_group:
-      - func: "fetch source"
-      - func: "create expansions"
-      - command: ec2.assume_role
-        params:
-          role_arn: ${aws_test_secrets_role}
-      - command: shell.exec
-        params:
-          shell: "bash"
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/setup-secrets.sh serverless_next
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/create-instance.sh
-      - command: expansions.update
-        params:
-          file: serverless-expansion.yml
-    teardown_task:
-      - command: shell.exec
-        params:
-          script: |
-            ${PREPARE_SHELL}
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/setup-secrets.sh serverless_next
-            bash ${DRIVERS_TOOLS}/.evergreen/serverless/delete-instance.sh
-      - func: "upload test results"
-    tasks:
-      - "test-serverless"
-
   - name: testatlas_task_group
     setup_group_can_fail_task: true
     setup_group_timeout_secs: 1800 # 30 minutes
@@ -752,26 +693,12 @@ tasks:
   - name: "test-atlas"
     commands:
       - func: "run Atlas tests"
-  - name: "test-serverless"
-    commands:
-      - func: "export FLE credentials"
-      - func: "run serverless tests"
-  - name: "test-docker"
-    commands:
-      - func: "build and test docker image"
   - name: "test-mlaunch"
     commands:
       - func: "run tests"
   - name: "driver-bench"
     commands:
       - func: "run benchmarks"
-  - name: "test-via-docker"
-    commands:
-      - func: "run tests via docker"
-  - name: "test-kerberos-integration"
-    commands:
-      - func: "export Kerberos credentials"
-      - func: "run Kerberos integration tests"
   - name: "test-kerberos"
     commands:
       - func: "run Kerberos unit tests"
@@ -779,10 +706,6 @@ tasks:
     commands:
       - func: "export FLE credentials"
       - func: "run tests"
-  - name: "test-fle-via-docker"
-    commands:
-      - func: "export FLE credentials"
-      - func: "run tests via docker"
   - name: "test-aws-auth"
     commands:
       - func: "export AWS auth credentials"
diff --git a/.evergreen/config/standard.yml.erb b/.evergreen/config/standard.yml.erb
index 668e65a9b1..53bf417758 100644
--- a/.evergreen/config/standard.yml.erb
+++ b/.evergreen/config/standard.yml.erb
@@ -29,10 +29,10 @@
   latest_stable_mdb = "7.0".inspect # so it gets quoted as a string
 
   # A few of the most recent MongoDB versions
-  actual_and_upcoming_mdb = %w( latest 7.0 6.0 )
+  actual_and_upcoming_mdb = %w( 7.0 6.0 )
 
-  recent_mdb = %w( 6.0 5.3 )
-  latest_5x_mdb = "5.3".inspect # so it gets quoted as a string
+  recent_mdb = %w( 6.0 5.0 )
+  latest_5x_mdb = "5.0".inspect # so it gets quoted as a string
 %>
 
 buildvariants:
@@ -41,7 +41,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: standalone
-    run_on: rhel80-large
+      os: ubuntu2204
     display_name: DriverBench
     tasks:
       - name: "driver-bench"
@@ -52,7 +52,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= actual_and_upcoming_mdb %>
       topology: <%= topologies %>
-      os: rhel8
+      os: ubuntu2204
     display_name: ${auth-and-ssl} ${ruby} db-${mongodb-version} ${topology}
     tasks:
       - name: "test-mlaunch"
@@ -62,10 +62,8 @@ buildvariants:
       ruby: <%= recent_rubies %>
       mongodb-version: <%= actual_and_upcoming_mdb %>
       topology: <%= topologies %>
-      os: ['rhel8']
-      # There is no latest for ubuntu2204, so we can't test it here.
-      # os: ['rhel8', 'ubuntu2204']
-    display_name: "${mongodb-version} ${os} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} ${os} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -74,18 +72,18 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= actual_and_upcoming_mdb %>
       topology: <%= topologies %>
-      os: 'rhel8-arm'
-    display_name: "${mongodb-version} ${os} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204-arm
+    display_name: "${mongodb-version} ${os} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
   - matrix_name: "mongo-5.x"
     matrix_spec:
       ruby: <%= sample_rubies %>
-      mongodb-version: ['5.3', '5.0']
+      mongodb-version: '5.0'
       topology: <%= topologies %>
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu1804
+    display_name: "${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -94,8 +92,8 @@ buildvariants:
       ruby: <%= older_rubies %>
       mongodb-version: ['4.4', '4.2', '4.0']
       topology: <%= topologies %>
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu1804
+    display_name: "${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -104,8 +102,8 @@ buildvariants:
       ruby: "ruby-2.7"
       mongodb-version: ['3.6']
       topology: <%= topologies %>
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu1804
+    display_name: "${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -115,19 +113,19 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: load-balanced
       single-mongos: single-mongos
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} single-lb ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} ${topology} single-lb ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
-  - matrix_name: "mongo-5.0-api-version"
+  - matrix_name: "mongo-api-version"
     matrix_spec:
       ruby: <%= latest_ruby %>
-      mongodb-version: '5.0'
+      mongodb-version: '7.0'
       topology: standalone
       api-version-required: yes
-      os: rhel8
-    display_name: "${mongodb-version} api-version-required ${topology} ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} api-version-required ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -137,8 +135,8 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: "sharded-cluster"
       single-mongos: single-mongos
-      os: rhel8
-    display_name: "${mongodb-version} ${topology} single-mongos ${auth-and-ssl} ${ruby}"
+      os: ubuntu2204
+    display_name: "${mongodb-version} ${topology} single-mongos ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
@@ -148,7 +146,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: <%= topologies %>
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${retry-reads} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -159,7 +157,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: [replica-set, sharded-cluster]
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${retry-writes} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -170,7 +168,7 @@ buildvariants:
       mongodb-version: ['3.6', '4.0']
       topology: <%= topologies %>
       storage-engine: mmapv1
-      os: rhel8
+      os: ubuntu1804
     display_name: "${mongodb-version} ${topology} mmapv1 ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -181,7 +179,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: '*'
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${lint} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -192,7 +190,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: <%= topologies %>
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} fork ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -203,7 +201,7 @@ buildvariants:
       ruby: <%= supported_rubies %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: <%= topologies %>
-      os: rhel8
+      os: ubuntu2004
     display_name: "${mongodb-version} ${topology} solo ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -214,7 +212,7 @@ buildvariants:
       ruby: ["ruby-2.7"]
       mongodb-version: ['4.2', '4.0', '3.6']
       topology: replica-set
-      os: rhel8
+      os: ubuntu1804
     display_name: "${mongodb-version} ${topology} stress ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -225,7 +223,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= recent_mdb %>
       topology: replica-set
-      os: rhel8
+      os: ubuntu2004
     display_name: "${mongodb-version} ${topology} stress ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -234,14 +232,9 @@ buildvariants:
     matrix_spec:
       auth-and-ssl: "x509"
       ruby: <%= latest_ruby %>
-      # needs the latest_5x_mdb because run-tests.sh uses `mongo` to configure
-      # the server for certain auth mechanisms. Once run-tests.sh is made smart
-      # enough to install mongosh, and then use either mongo or mongosh
-      # (depending on server version and what's available), we can bump this to
-      # the latest stable db version.
-      mongodb-version: <%= latest_5x_mdb %>
+      mongodb-version: <%= latest_stable_mdb %>
       topology: standalone
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -252,7 +245,7 @@ buildvariants:
       ruby: <%= jrubies.first %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: <%= topologies %>
-      os: rhel8
+      os: ubuntu2204
     display_name: "${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -264,7 +257,7 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: "replica-set"
       compressor: 'zlib'
-      os: rhel8
+      os: ubuntu2004
     display_name: "${compressor} ${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -276,7 +269,7 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: "replica-set"
       compressor: 'snappy'
-      os: rhel8
+      os: ubuntu2004
     display_name: "${compressor} ${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -292,7 +285,7 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: "replica-set"
       compressor: 'zstd'
-      os: rhel8
+      os: ubuntu2004
     display_name: "${compressor} ${mongodb-version} ${topology} ${auth-and-ssl} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -303,7 +296,7 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: replica-set
       as: as
-      os: rhel8
+      os: ubuntu2004
     display_name: "AS ${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
@@ -314,50 +307,29 @@ buildvariants:
       mongodb-version: <%= latest_stable_mdb %>
       topology: replica-set
       bson: "*"
-      os: rhel8
+      os: ubuntu2004
     display_name: "bson-${bson} ${mongodb-version} ${topology} ${ruby}"
     tasks:
       - name: "test-mlaunch"
 
-  # kerberos integration tests are broken (RUBY-3266)
-  # - matrix_name: "kerberos-integration"
-  #   matrix_spec:
-  #     ruby: <%= sample_rubies %>
-  #     os: rhel8
-  #   display_name: "Kerberos integration ${os} ${ruby}"
-  #   tasks:
-  #     - name: "test-kerberos-integration"
-
   - matrix_name: "kerberos-unit"
     matrix_spec:
       ruby: <%= latest_ruby %>
       mongodb-version: <%= latest_stable_mdb %>
       topology: standalone
-      os: rhel8
+      os: ubuntu2204
       auth-and-ssl: kerberos
     display_name: "Kerberos Tests"
     tasks:
       - name: "test-kerberos"
 
-  - matrix_name: "fle-latest"
-    matrix_spec:
-      auth-and-ssl: "noauth-and-nossl"
-      ruby: <%= latest_ruby %>
-      topology: [replica-set, sharded-cluster]
-      mongodb-version: [ 'latest', '7.0' ]
-      os: rhel8
-      fle: helper
-    display_name: "FLE: ${mongodb-version} ${topology} ${ruby}"
-    tasks:
-      - name: "test-fle"
-
   - matrix_name: "fle"
     matrix_spec:
       auth-and-ssl: "noauth-and-nossl"
-      ruby: <%= sample_mri_rubies %>
+      ruby: <%= latest_ruby %>
       topology: [replica-set, sharded-cluster]
-      mongodb-version: [ '6.0', '4.4', '4.2', '4.0' ]
-      os: rhel8
+      mongodb-version: [ '6.0', '7.0' ]
+      os: ubuntu2204
       fle: helper
     display_name: "FLE: ${mongodb-version} ${topology} ${ruby}"
     tasks:
@@ -388,7 +360,7 @@ buildvariants:
       ruby: <%= supported_mri_rubies %>
       topology: standalone
       mongodb-version: <%= latest_stable_mdb %>
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP verifier: ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -401,7 +373,7 @@ buildvariants:
       ruby: <%= sample_mri_rubies %>
       topology: standalone
       mongodb-version: <%= latest_stable_mdb %>
-      os: rhel8
+      os: ubuntu2004
       auth-and-ssl: noauth-and-ssl
     display_name: "OCSP integration - must staple: ${mongodb-version} ${ruby}"
     tasks:
@@ -414,7 +386,7 @@ buildvariants:
       ruby: <%= sample_mri_rubies %>
       topology: standalone
       mongodb-version: <%= latest_stable_mdb %>
-      os: rhel8
+      os: ubuntu2004
       auth-and-ssl: noauth-and-ssl
     display_name: "OCSP integration - unknown: ${mongodb-version} ${ruby}"
     tasks:
@@ -444,7 +416,7 @@ buildvariants:
       ruby: <%= sample_mri_rubies %>
       topology: standalone
       mongodb-version: <%= latest_stable_mdb %>
-      os: rhel8
+      os: ubuntu2004
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${extra-uri-options} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -465,7 +437,7 @@ buildvariants:
       ruby: <%= jrubies.first %>
       topology: standalone
       mongodb-version: <%= latest_stable_mdb %>
-      os: rhel8
+      os: ubuntu2204
     display_name: "OCSP connectivity: ${ocsp-algorithm} ${ocsp-status} ${ocsp-delegate} ${mongodb-version} ${ruby}"
     tasks:
       - name: test-mlaunch
@@ -475,7 +447,7 @@ buildvariants:
       ruby: <%= latest_ruby %>
       fle: helper
       topology: standalone
-      os: rhel8
+      os: ubuntu2204
       mongodb-version: <%= latest_stable_mdb %>
     display_name: "GCP KMS"
     tasks:
@@ -497,7 +469,7 @@ buildvariants:
   - matrix_name: atlas-full
     matrix_spec:
       ruby: <%= latest_ruby %>
-      os: rhel8
+      os: ubuntu2204
     display_name: "Atlas (Full)"
     tasks:
       - name: testatlas_full_task_group
@@ -505,37 +477,14 @@ buildvariants:
   - matrix_name: "atlas"
     matrix_spec:
       ruby: <%= supported_rubies %>
-      os: rhel8
+      os: ubuntu2004
     display_name: "Atlas tests ${ruby}"
     tasks:
        - name: testatlas_task_group
 
-# Commented out, pending RUBY-3414
-#  - matrix_name: "serverless"
-#    matrix_spec:
-#      # https://jira.mongodb.org/browse/RUBY-3217
-#      # ruby: <%= supported_rubies %>
-#      ruby: <%= supported_mri_rubies %>
-#      fle: path
-#      os: rhel8
-#    display_name: "Atlas serverless ${ruby}"
-#    tasks:
-#       - name: serverless_task_group
-#
-#  - matrix_name: "serverless-next"
-#    matrix_spec:
-#      # https://jira.mongodb.org/browse/RUBY-3217
-#      # ruby: <%= supported_rubies %>
-#      ruby: <%= supported_mri_rubies %>
-#      fle: path
-#      os: rhel8
-#    display_name: "Atlas serverless-next ${ruby}"
-#    tasks:
-#       - name: serverless_next_task_group
-
   - matrix_name: "aws-lambda"
     matrix_spec:
-      ruby: <%= latest_ruby %>
+      ruby: 'ruby-3.2'
       os: ubuntu2204
     display_name: "AWS Lambda"
     tasks:
diff --git a/.evergreen/run-tests.sh b/.evergreen/run-tests.sh
index a2203eb79a..6916698f31 100755
--- a/.evergreen/run-tests.sh
+++ b/.evergreen/run-tests.sh
@@ -41,7 +41,7 @@ set_env_vars
 set_env_python
 set_env_ruby
 
-prepare_server $arch
+prepare_server
 
 if test "$DOCKER_PRELOAD" != 1; then
   install_mlaunch_venv
@@ -110,7 +110,7 @@ elif test "$AUTH" = x509; then
 EOT
   `"
 
-  "$BINDIR"/mongo --tls \
+  "$BINDIR"/mongosh --tls \
     --tlsCAFile spec/support/certificates/ca.crt \
     --tlsCertificateKeyFile spec/support/certificates/client-x509.pem \
     -u bootstrap -p bootstrap \
@@ -278,7 +278,7 @@ fi
 export MONGODB_URI="mongodb://$hosts/?serverSelectionTimeoutMS=30000$uri_options"
 
 if echo "$AUTH" |grep -q ^aws-assume-role; then
-  $BINDIR/mongo "$MONGODB_URI" --eval 'db.runCommand({serverStatus: 1})' |wc
+  $BINDIR/mongosh "$MONGODB_URI" --eval 'db.runCommand({serverStatus: 1})' |wc
 fi
 
 set_fcv
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e3f468fe8b..eed6da1e33 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -3,7 +3,7 @@
 # the standalone one.
 
 name: Run Driver Tests
-on: [push, pull_request]
+on: [ workflow_dispatch ]
 jobs:
   build:
     name: "${{matrix.os}} ruby-${{matrix.ruby}} mongodb-${{matrix.mongodb}} ${{matrix.topology}}"
diff --git a/.gitmodules b/.gitmodules
index 6d428f359d..366d171c3a 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -3,4 +3,4 @@
 	url = https://github.com/mongodb-labs/drivers-evergreen-tools
 [submodule "spec/shared"]
 	path = spec/shared
-	url = git@github.com:mongodb-labs/mongo-ruby-spec-shared.git
+	url = https://github.com/mongodb-labs/mongo-ruby-spec-shared
diff --git a/.mod/drivers-evergreen-tools b/.mod/drivers-evergreen-tools
index 8c948a286f..9142b7055e 160000
--- a/.mod/drivers-evergreen-tools
+++ b/.mod/drivers-evergreen-tools
@@ -1 +1 @@
-Subproject commit 8c948a286f1b82427b5a409b8c42475b599d4d6f
+Subproject commit 9142b7055ea5940e59ad41c4b069376f867031da
diff --git a/lib/mongo/socket/ssl.rb b/lib/mongo/socket/ssl.rb
index 10bb7b4d6c..747896b33f 100644
--- a/lib/mongo/socket/ssl.rb
+++ b/lib/mongo/socket/ssl.rb
@@ -23,6 +23,7 @@ class Socket
     # @since 2.0.0
     class SSL < Socket
       include OpenSSL
+      include Loggable
 
       # Initializes a new TLS socket.
       #
@@ -363,12 +364,15 @@ def verify_certificate!(socket)
       end
 
       def verify_ocsp_endpoint!(socket)
-        unless verify_ocsp_endpoint?
-          return
-        end
+        return unless verify_ocsp_endpoint?
 
         cert = socket.peer_cert
-        ca_cert = socket.peer_cert_chain.last
+        ca_cert = find_issuer(cert, socket.peer_cert_chain)
+
+        unless ca_cert
+          log_warn("TLS certificate of '#{host_name}' could not be definitively verified via OCSP: issuer certificate not found in the chain.")
+          return
+        end
 
         verifier = OcspVerifier.new(@host_name, cert, ca_cert, context.cert_store,
           **Utils.shallow_symbolize_keys(options))
@@ -411,6 +415,11 @@ def extract_certs(text)
           end
         end
       end
+
+      # Find the issuer certificate in the chain.
+      def find_issuer(cert, cert_chain)
+        cert_chain.find { |c| c.subject == cert.issuer }
+      end
     end
   end
 end
diff --git a/profile/driver_bench/rake/tasks.rake b/profile/driver_bench/rake/tasks.rake
index 7614a3a44c..44bcfb5049 100644
--- a/profile/driver_bench/rake/tasks.rake
+++ b/profile/driver_bench/rake/tasks.rake
@@ -2,7 +2,7 @@
 
 task driver_bench: %i[ driver_bench:data driver_bench:run ]
 
-SPECS_REPO_URI = 'git@github.com:mongodb/specifications.git'
+SPECS_REPO_URI = 'https://github.com/mongodb/specifications'
 SPECS_PATH = File.expand_path('../../../specifications', __dir__)
 DRIVER_BENCH_DATA = File.expand_path('../../data/driver_bench', __dir__)
 
diff --git a/spec/integration/ocsp_verifier_spec.rb b/spec/integration/ocsp_verifier_spec.rb
index 7cdfaabc70..de061aa925 100644
--- a/spec/integration/ocsp_verifier_spec.rb
+++ b/spec/integration/ocsp_verifier_spec.rb
@@ -9,6 +9,21 @@
   with_openssl_debug
   retry_test sleep: 5
 
+  def self.with_ocsp_responder(port = 8100, path = '/', &setup)
+    around do |example|
+      server = WEBrick::HTTPServer.new(Port: port)
+      server.mount_proc path, &setup
+      Thread.new { server.start }
+      begin
+        example.run
+      ensure
+        server.shutdown
+      end
+
+      ::Utils.wait_for_port_free(port, 5)
+    end
+  end
+
   shared_examples 'verifies' do
     context 'mri' do
       fails_on_jruby
@@ -173,21 +188,10 @@
 
     context 'one time' do
 
-      around do |example|
-        server = WEBrick::HTTPServer.new(Port: 8100)
-        server.mount_proc '/' do |req, res|
-          res.status = 303
-          res['locAtion'] = "http://localhost:8101#{req.path}"
-          res.body = "See http://localhost:8101#{req.path}"
-        end
-        Thread.new { server.start }
-        begin
-          example.run
-        ensure
-          server.shutdown
-        end
-
-        ::Utils.wait_for_port_free(8100, 5)
+      with_ocsp_responder do |req, res|
+        res.status = 303
+        res['locAtion'] = "http://localhost:8101#{req.path}"
+        res.body = "See http://localhost:8101#{req.path}"
       end
 
       include_context 'verifier', algorithm: algorithm
@@ -248,21 +252,10 @@
         port: 8101,
       )
 
-      around do |example|
-        server = WEBrick::HTTPServer.new(Port: 8100)
-        server.mount_proc '/' do |req, res|
-          res.status = 303
-          res['locAtion'] = req.path
-          res.body = "See #{req.path} indefinitely"
-        end
-        Thread.new { server.start }
-        begin
-          example.run
-        ensure
-          server.shutdown
-        end
-
-        ::Utils.wait_for_port_free(8100, 5)
+      with_ocsp_responder do |req, res|
+        res.status = 303
+        res['locAtion'] = req.path
+        res.body = "See #{req.path} indefinitely"
       end
 
       include_context 'verifier', algorithm: algorithm
@@ -274,85 +267,23 @@
 
     include_context 'verifier', algorithm: 'rsa'
 
-    context '40x / 50x' do
-      around do |example|
-        server = WEBrick::HTTPServer.new(Port: 8100)
-        server.mount_proc '/' do |req, res|
+    [400, 404, 500, 503].each do |code|
+      context "code #{code}" do
+        with_ocsp_responder do |req, res|
           res.status = code
           res.body = "HTTP #{code}"
         end
-        Thread.new { server.start }
-        begin
-          example.run
-        ensure
-          server.shutdown
-        end
-
-        ::Utils.wait_for_port_free(8100, 5)
-      end
-
-      [400, 404, 500, 503].each do |_code|
-        context "code #{_code}" do
-          let(:code) { _code }
-          include_examples 'does not verify'
-        end
-      end
-    end
-
-    context '204' do
-      around do |example|
-        server = WEBrick::HTTPServer.new(Port: 8100)
-        server.mount_proc '/' do |req, res|
-          res.status = 204
-        end
-        Thread.new { server.start }
-        begin
-          example.run
-        ensure
-          server.shutdown
-        end
 
-        ::Utils.wait_for_port_free(8100, 5)
-      end
-
-      context "code 204" do
-        let(:code) { 204 }
         include_examples 'does not verify'
       end
     end
-  end
-
-  context 'responder URI has no path' do
-    require_external_connectivity
-
-    # https://github.com/jruby/jruby-openssl/issues/210
-    fails_on_jruby
 
-    include_context 'basic verifier'
-
-    # The fake certificates all have paths in them for use with the ocsp mock.
-    # Use real certificates retrieved from Atlas for this test as they don't
-    # have a path in the OCSP URI (which the test also asserts).
-    # Note that these certificates expire in 3 months and need to be replaced
-    # with a more permanent solution.
-    # Use the spec/support/certificates/retrieve-atlas-cert script to retrieve
-    # current certificates from Atlas.
-    let(:cert_path) { File.join(File.dirname(__FILE__), '../support/certificates/atlas-ocsp.crt') }
-    let(:ca_cert_path) { File.join(File.dirname(__FILE__), '../support/certificates/atlas-ocsp-ca.crt') }
-    let(:cert_store) do
-      OpenSSL::X509::Store.new.tap do |store|
-        store.set_default_paths
+    context 'code 204' do
+      with_ocsp_responder do |req, res|
+        res.status = 204
       end
-    end
-
-    before do
-      verifier.ocsp_uris.length.should > 0
-      URI.parse(verifier.ocsp_uris.first).path.should == ''
-    end
 
-    it 'verifies' do
-      # TODO This test will fail if the certificate expires
-      expect(verifier.verify).to be(true), "If atlas-ocsp certificates have expired, run spec/support/certificates/retrieve-atlas-cert to get a new ones"
+      include_examples 'does not verify'
     end
   end
 end
diff --git a/spec/integration/reconnect_spec.rb b/spec/integration/reconnect_spec.rb
index f478e233dd..6d210251da 100644
--- a/spec/integration/reconnect_spec.rb
+++ b/spec/integration/reconnect_spec.rb
@@ -111,6 +111,10 @@
       # thread.kill should've similarly failed, but it doesn't.
       fails_on_jruby
 
+      # odd failures related to async on ruby <= 3.1, I suspect something
+      # with how fibers worked in those versions.
+      minimum_mri_version '3.2.0'
+
       it 'recreates SRV monitor' do
         wait_for_discovery
 
@@ -151,6 +155,10 @@
       # NotImplementedError: recvmsg_nonblock is not implemented
       fails_on_jruby
 
+      # odd failures related to async on ruby <= 3.1, I suspect something
+      # with how fibers worked in those versions.
+      minimum_mri_version '3.2.0'
+
       let(:uri) do
         "mongodb+srv://test-fake.test.build.10gen.cc/"
       end
@@ -181,8 +189,6 @@
       end
 
       around do |example|
-        require 'support/dns'
-
         rules = [
           ['_mongodb._tcp.test-fake.test.build.10gen.cc', :srv,
             [0, 0, 2799, 'localhost.test.build.10gen.cc'],
diff --git a/spec/integration/srv_monitoring_spec.rb b/spec/integration/srv_monitoring_spec.rb
index 6d7da1f730..8c3d1560a1 100644
--- a/spec/integration/srv_monitoring_spec.rb
+++ b/spec/integration/srv_monitoring_spec.rb
@@ -76,9 +76,8 @@
     # NotImplementedError: recvmsg_nonblock is not implemented
     fails_on_jruby
 
-    before(:all) do
-      require 'support/dns'
-    end
+    # mock dns implementation doesn't play nice with 2.7, etc.
+    minimum_mri_version '3.0.0'
 
     around do |example|
       # Speed up the tests by listening on the fake ports we are using.
diff --git a/spec/integration/srv_spec.rb b/spec/integration/srv_spec.rb
index da3d529339..594ff9e69b 100644
--- a/spec/integration/srv_spec.rb
+++ b/spec/integration/srv_spec.rb
@@ -12,10 +12,6 @@
     # NotImplementedError: recvmsg_nonblock is not implemented
     fails_on_jruby
 
-    before(:all) do
-      require 'support/dns'
-    end
-
     let(:uri) do
       "mongodb+srv://test-fake.test.build.10gen.cc/?tls=#{SpecConfig.instance.ssl?}&tlsInsecure=true"
     end
diff --git a/spec/shared b/spec/shared
index cee4bc0264..1017c94e4b 160000
--- a/spec/shared
+++ b/spec/shared
@@ -1 +1 @@
-Subproject commit cee4bc02649a573c8256b0505c1d23f503ac2609
+Subproject commit 1017c94e4b0962d3b68eced52566e700ae4e70b4
diff --git a/spec/support/common_shortcuts.rb b/spec/support/common_shortcuts.rb
index 32d386b36a..7a4fe09e17 100644
--- a/spec/support/common_shortcuts.rb
+++ b/spec/support/common_shortcuts.rb
@@ -337,51 +337,33 @@ def stop_monitoring(*clients)
       [:tcp, "0.0.0.0", 5300],
     ]
 
-    def mock_dns(config)
-      semaphore = Mongo::Semaphore.new
-
-      thread = Thread.new do
-        RubyDNS::run_server(DNS_INTERFACES) do
-          config.each do |(query, type, *answers)|
-
-            resource_cls = Resolv::DNS::Resource::IN.const_get(type.to_s.upcase)
-            resources = answers.map do |answer|
-              resource_cls.new(*answer)
-            end
-            match(query, resource_cls) do |req|
-              req.add(resources)
-            end
+    # Starts the DNS server and returns it; should be run from within an
+    # Async block. Prefer #mock_dns instead, which does the setup for you.
+    def start_dns_server(config)
+      RubyDNS::run_server(DNS_INTERFACES) do
+        config.each do |(query, type, *answers)|
+          resource_cls = Resolv::DNS::Resource::IN.const_get(type.to_s.upcase)
+          resources = answers.map do |answer|
+            resource_cls.new(*answer)
           end
 
-          semaphore.signal
+          match(query, resource_cls) do |req|
+            req.add(resources)
+          end
         end
       end
+    end
 
-      semaphore.wait
+    # Starts and runs a DNS server, then yields to the attached block.
+    def mock_dns(config)
+      # only require rubydns when we need it; it's MRI-only.
+      require 'rubydns'
 
-      begin
+      Async do |task|
+        server = start_dns_server(config)
         yield
       ensure
-        10.times do
-          if $last_async_task
-            break
-          end
-          sleep 0.5
-        end
-
-        # Hack to stop the server - https://github.com/socketry/rubydns/issues/75
-        if $last_async_task.nil?
-          STDERR.puts "No async task - server never started?"
-        else
-          begin
-            $last_async_task.stop
-          rescue NoMethodError => e
-            STDERR.puts "Error stopping async task: #{e}"
-          end
-        end
-
-        thread.kill
-        thread.join
+        server.stop
       end
     end
 
diff --git a/spec/support/constraints.rb b/spec/support/constraints.rb
index 6d92409937..8c7f3f940d 100644
--- a/spec/support/constraints.rb
+++ b/spec/support/constraints.rb
@@ -17,6 +17,16 @@ def require_local_tls
     end
   end
 
+  def minimum_mri_version(version)
+    require_mri
+
+    before(:all) do
+      if RUBY_VERSION < version
+        skip "Ruby #{version} or greater is required"
+      end
+    end
+  end
+
   def forbid_x509_auth
     before(:all) do
       skip 'X.509 auth not allowed' if SpecConfig.instance.x509_auth?
diff --git a/spec/support/dns.rb b/spec/support/dns.rb
deleted file mode 100644
index d868f7bc3b..0000000000
--- a/spec/support/dns.rb
+++ /dev/null
@@ -1,16 +0,0 @@
-# frozen_string_literal: true
-# rubocop:todo all
-
-require 'rubydns'
-
-# Hack to stop the server - https://github.com/socketry/rubydns/issues/75
-module Async
-  class Task
-    alias :run_without_record :run
-    def run(*args)
-      run_without_record.tap do
-        $last_async_task = self
-      end
-    end
-  end
-end