diff --git a/Dockerfile b/Dockerfile
index 7b73010..5d66291 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,6 +13,7 @@ FROM nextcloud:17
 # CMD cron && apache2-foreground
 
 # Mandatory for bookmark extension
-RUN apt-get update \
- && apt-get install -y php7.3-gmp
+# but missing from deb packages
+# RUN apt-get update \
+# && apt-get install -y php7.3-gmp