diff --git a/server/modules/rendering/markdown-plantuml/renderer.js b/server/modules/rendering/markdown-plantuml/renderer.js
index 86cb5bca..ddcb5fc1 100644
--- a/server/modules/rendering/markdown-plantuml/renderer.js
+++ b/server/modules/rendering/markdown-plantuml/renderer.js
@@ -112,7 +112,7 @@ module.exports = {
           altToken
         )
 
-        var zippedCode = encode64(zlib.deflateSync('@startuml\n' + contents + '\n@enduml').toString('binary'))
+        var zippedCode = encode64(zlib.deflateRawSync('@startuml\n' + contents + '\n@enduml').toString('binary'))
 
         token = state.push('uml_diagram', 'img', 0)
         // alt is constructed from children. No point in populating it here.