diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 93c4937e35760480c805c1919151c9966dda0038..20501b8a6af79e2d744ea0affb3d600b3209badc 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,7 +6,7 @@
     fi
   - |
     export CI_APP_REPO=${CI_APP_REPO:-$CI_REGISTRY_IMAGE}
-    if [[ $CI_COMMIT_BRANCH == "master" ]]; then
+    if [[ $CI_COMMIT_BRANCH == "main" ]]; then
       export CI_APP_TAG=${CI_APP_TAG:-latest}
     elif [[ $CI_COMMIT_BRANCH == "freeze-version" ]]; then
       export CI_APP_TAG=${CI_APP_TAG:-$GHC_VERSION_BUILD}
@@ -55,7 +55,7 @@ build:latest-linux-amd64:
       docker push $CI_APP_REPO:$CI_APP_TAG-linux-amd64
       docker push $CI_APP_REPO:$VERSION_MAJ_MIN_PAT-linux-amd64
   rules:
-    - if: $CI_COMMIT_BRANCH == "master" && $CI_BUILD_PLATFORMS =~ /(linux\/amd64)/
+    - if: $CI_COMMIT_BRANCH == "main" && $CI_BUILD_PLATFORMS =~ /(linux\/amd64)/
       changes:
         - latest.Dockerfile
 
@@ -76,7 +76,7 @@ build:latest-linux-arm64v8:
       docker push $CI_APP_REPO:$CI_APP_TAG-linux-arm64v8
       docker push $CI_APP_REPO:$VERSION_MAJ_MIN_PAT-linux-arm64v8
   rules:
-    - if: $CI_COMMIT_BRANCH == "master" && $CI_BUILD_PLATFORMS =~ /(linux\/arm64\/v8)/
+    - if: $CI_COMMIT_BRANCH == "main" && $CI_BUILD_PLATFORMS =~ /(linux\/arm64\/v8)/
       changes:
         - latest.Dockerfile
 
@@ -149,7 +149,7 @@ build-manifest:latest-linux-multiarch:
       fi
       docker manifest push $CI_APP_REPO:$VERSION_MAJ
   rules:
-    - if: $CI_COMMIT_BRANCH == "master"
+    - if: $CI_COMMIT_BRANCH == "main"
       changes:
         - latest.Dockerfile
 
diff --git a/bootstrap/arm64.Dockerfile b/bootstrap/arm64.Dockerfile
index 504b9452a9c1aaadc5bfc670908a24c32aea009f..766c2b6f828e2598dcbc3916757dbca920f90a4c 100644
--- a/bootstrap/arm64.Dockerfile
+++ b/bootstrap/arm64.Dockerfile
@@ -26,7 +26,7 @@ RUN apk add --update --no-cache \
     zlib-dev
 
 RUN cd /tmp/ \
-  && wget https://gitlab.b-data.ch/ghc/ghc-bootstrap-aarch64/-/raw/master/ghc-8.8.3-r0.apk \
+  && wget https://gitlab.b-data.ch/ghc/ghc-bootstrap-aarch64/-/raw/main/ghc-8.8.3-r0.apk \
   && apk add --allow-untrusted ghc-8.8.3-r0.apk \
   && curl -sSLO https://downloads.haskell.org/~cabal/cabal-install-$CABAL_VERSION/cabal-install-$CABAL_VERSION.tar.gz \
   && tar zxf cabal-install-$CABAL_VERSION.tar.gz \
@@ -74,7 +74,7 @@ RUN apk add --update --no-cache \
     zlib-dev \
     #zlib-static \
   && cd /tmp/ \
-  && wget https://gitlab.b-data.ch/ghc/ghc-bootstrap-aarch64/-/raw/master/ghc-8.8.3-r0.apk \
+  && wget https://gitlab.b-data.ch/ghc/ghc-bootstrap-aarch64/-/raw/main/ghc-8.8.3-r0.apk \
   && apk add --allow-untrusted ghc-8.8.3-r0.apk \
   && cd / \
   && rm -rf /tmp/*