diff --git a/Dockerfile b/Dockerfile
index 1b2a607..cbefa82 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -113,7 +113,7 @@ RUN \
   echo "**** build kasmvnc ****" && \
   git clone https://github.com/kasmtech/KasmVNC.git src && \
   cd /src && \
-  git checkout -f ${KASMVNC_release} && \
+  git checkout -f ${KASMVNC_RELEASE} && \
   sed -i \
     -e '/find_package(FLTK/s@^@#@' \
     -e '/add_subdirectory(tests/s@^@#@' \
diff --git a/Dockerfile.aarch64 b/Dockerfile.aarch64
index b2040e1..d6e0f93 100644
--- a/Dockerfile.aarch64
+++ b/Dockerfile.aarch64
@@ -117,7 +117,7 @@ RUN \
   echo "**** build kasmvnc ****" && \
   git clone https://github.com/kasmtech/KasmVNC.git src && \
   cd /src && \
-  git checkout -f ${KASMVNC_release} && \
+  git checkout -f ${KASMVNC_RELEASE} && \
   sed -i \
     -e '/find_package(FLTK/s@^@#@' \
     -e '/add_subdirectory(tests/s@^@#@' \