diff --git a/Dockerfile b/Dockerfile
index 4c44ba0..1d909d1 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -30,6 +30,7 @@ RUN \
   apk add --no-cache --virtual=build-dependencies \
     build-base \
     git \
+    grep \
     libffi-dev \
     mariadb-dev \
     nodejs \
@@ -55,7 +56,8 @@ RUN \
   corepack enable && \
   yarn install && \
   gem install foreman && \
-  sed -i 's/\d.\d.\d/3.3.3/' .ruby-version && \
+  RUBY=$(apk list ruby | grep -oP '.*-\K(\d\.\d\.\d)') && \
+  sed -i "s/\d.\d.\d/${RUBY}/" .ruby-version && \
   bundle config set --local deployment 'true' && \
   bundle config set --local without 'development test' && \
   bundle config force_ruby_platform true && \
diff --git a/Dockerfile.aarch64 b/Dockerfile.aarch64
index 325246c..3f9bbd9 100644
--- a/Dockerfile.aarch64
+++ b/Dockerfile.aarch64
@@ -30,6 +30,7 @@ RUN \
   apk add --no-cache --virtual=build-dependencies \
     build-base \
     git \
+    grep \
     libffi-dev \
     mariadb-dev \
     nodejs \
@@ -55,7 +56,8 @@ RUN \
   corepack enable && \
   yarn install && \
   gem install foreman && \
-  sed -i 's/\d.\d.\d/3.3.3/' .ruby-version && \
+  RUBY=$(apk list ruby | grep -oP '.*-\K(\d\.\d\.\d)') && \
+  sed -i "s/\d.\d.\d/${RUBY}/" .ruby-version && \
   bundle config set --local deployment 'true' && \
   bundle config set --local without 'development test' && \
   bundle config force_ruby_platform true && \