diff --git a/Rakefile b/Rakefile
index 4569d1e..38c7b73 100644
--- a/Rakefile
+++ b/Rakefile
@@ -2,7 +2,8 @@ task :get_image_version do
   dockerfile_content = IO.read("transport-site/Dockerfile")
   version = dockerfile_content[/FROM (hexpm\/elixir.*)/, 1]
   version = version.gsub('hexpm/elixir:','elixir-')
-  tools_version = dockerfile_content[/transport-tools:v(\d+\.\d+\.\d+) as transport-tools/, 1]
-  fail "Unexpected FROM value (got #{version}), script must be adapted?" unless version =~ /\Aelixir\-[^\-]+\-erlang\-[^\-]+\-ubuntu\-focal\-[^\-]+\z/
+  tools_version = dockerfile_content[/transport-tools:v(\d+\.\d+\.\d+) as transport-tools/i, 1]
+  fail "Unexpected FROM value (got #{version.inspect}), script must be adapted?" unless version =~ /\Aelixir\-[^\-]+\-erlang\-[^\-]+\-ubuntu\-focal\-[^\-]+\z/
+  fail "Unexpected tools_version value (got #{tools_version.inspect}), script must be adapted?" unless tools_version =~ /\A\d\.\d\.\d\z/
   puts version + "-transport-tools-" + tools_version
 end