diff --git a/.ci/Jenkinsfile b/.ci/Jenkinsfile
index 4891f2d0cfe661a7424e83d7588118992b3010ef..20548768e2b544c3c0f599541d8a7273f1d6b1d3 100755
--- a/.ci/Jenkinsfile
+++ b/.ci/Jenkinsfile
@@ -35,7 +35,7 @@ pipeline {
 		stage('Container Build') {
 			agent { label 'conviz1||conviz2' }
 			environment {
-				DOCKER_BASE_IMAGE = "debian:buster"
+				DOCKER_BASE_IMAGE = "debian:bullseye"
 				// FIXME: ^${DEPENDENCY_PYTHON} is a workaround for an invalid spectrum-mpi concretization
 				DEPENDENCY_PYTHON = "python@2.7.18"
 				// This needs to be here because otherwise the default python
diff --git a/.ci/commons.sh b/.ci/commons.sh
index 76d5869ebbd1c025ecb6473106e1ed4e38c76aa9..ef43c8c024de65588e3f94c48b09662cea96e02d 100755
--- a/.ci/commons.sh
+++ b/.ci/commons.sh
@@ -639,7 +639,7 @@ get_latest_hash() {
   # insert compiler name into spec name at appropriate position (i.e., prior to
   # specifying any variants)
   # \$1 is the hash, \$2 is the spec
-  idx = match(\$2, /(\\+|\\~|$)/);
+  idx = match(\$2, /(\\+|~|$)/);
   printf("%s%%%s%s /%s\\n", substr(\$2, 0, idx-1), compiler, substr(\$2, idx), \$1)
 }
 EOF
diff --git a/.ci/install_prerequisites.sh b/.ci/install_prerequisites.sh
index b47c43275e8280bae4ddf1f123a39e162a693313..07b1b27639367a9142c94227c44dea39322d687b 100755
--- a/.ci/install_prerequisites.sh
+++ b/.ci/install_prerequisites.sh
@@ -25,8 +25,6 @@ prerequisites=(
     "patch"
     "patchelf"
     "procps"
-    "python"
-    "python-yaml"
     "python3"
     "python3-yaml"
     "rsync"