diff --git a/tox.ini b/tox.ini
index 4d940258134..9e737e25dd3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -163,7 +163,6 @@ passenv =
     docker:       DOCKER_CONFIG_FILE
     docker-incremental: FROM_DOCKER_REPOSITORY
     docker-incremental: FROM_DOCKER_TARGET
-    docker-incremental: FROM_DOCKER_TAG
     local:        MAKE
     local:        PREFIX
     local:        SAGE_NUM_THREADS
@@ -501,7 +500,8 @@ setenv =
     # Resulting full image:tag name
     #
     docker:             FULL_BASE_IMAGE_AND_TAG={env:ARCH_IMAGE_PREFIX:}{env:BASE_IMAGE}{env:ARCH_IMAGE_SUFFIX:}:{env:ARCH_TAG_PREFIX:}{env:BASE_TAG}{env:ARCH_TAG_SUFFIX:}
-    docker-incremental: FULL_BASE_IMAGE_AND_TAG={env:FROM_DOCKER_REPOSITORY:ghcr.io/sagemath/sage/}sage-$(echo {envname} | sed -E "s/(docker-|-incremental|-sitepackages)//g")-{env:FROM_DOCKER_TARGET:with-targets}:{env:FROM_DOCKER_TAG:dev}
+    docker-incremental: FULL_BASE_IMAGE_AND_TAG={env:FROM_DOCKER_REPOSITORY:ghcr.io/sagemath/sage/}sage-$(echo {envname} | sed -E "s/(docker-|-incremental|-sitepackages)//g")-{env:FROM_DOCKER_TARGET:with-targets}:10.8.beta5
+    docker-incremental: FROM_DOCKER_TAG=10.8.beta5
     # Can SKIP_SYSTEM_PKG_INSTALL if the base image already has git
     docker-incremental-{develop,recommended,maximal}:   SKIP_SYSTEM_PKG_INSTALL=yes
     docker-incremental-sitepackages:                    SKIP_SYSTEM_PKG_INSTALL=no