diff --git a/Dockerfile b/Dockerfile
index 59fb734..7b73010 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -13,6 +13,6 @@ FROM nextcloud:17
 # CMD cron && apache2-foreground
 
 # Mandatory for bookmark extension
-RUN docker-php-ext-configure gmp; \
-      docker-php-ext-install gmp
+RUN apt-get update \
+ && apt-get install -y php7.3-gmp