diff --git a/index.js b/index.js
index e0144a5..4512b78 100644
--- a/index.js
+++ b/index.js
@@ -108,7 +108,7 @@ function fastifyCompress (fastify, opts, next) {
   next()
 }
 
-const defaultCompressibleTypes = /^text\/(?!event-stream)|(?:\+|\/)json(?:;|$)|(?:\+|\/)text(?:;|$)|(?:\+|\/)xml(?:;|$)|octet-stream(?:;|$)/
+const defaultCompressibleTypes = /^text\/(?!event-stream)|(?:\+|\/)json(?:;|$)|(?:\+|\/)text(?:;|$)|(?:\+|\/)xml(?:;|$)|octet-stream(?:;|$)/u
 
 function processCompressParams (opts) {
   /* istanbul ignore next */