diff --git a/docker/Dockerfile b/docker/Dockerfile
index bb37f69..ae3118d 100755
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -16,7 +16,7 @@ RUN ln -sf "/usr/share/zoneinfo/${TZ}" /etc/localtime && \
     echo "${TZ}" > /etc/timezone && date
 
 # Cache Bust upon new commits
-ADD https://api.github.com/repos/chrisb86/nsupdate/git/refs/heads/master /.git-hashref
+ADD https://api.github.com/repos/chrisb86/nsupdate/git/refs/heads/main /.git-hashref
 
 COPY nsupdate.sh /usr/local/bin/nsupdate.sh
 RUN chmod +x /usr/local/bin/nsupdate.sh