diff --git a/.docker/dev/php/Dockerfile b/.docker/dev/php/Dockerfile
index 394a14e10..4a2b7497f 100644
--- a/.docker/dev/php/Dockerfile
+++ b/.docker/dev/php/Dockerfile
@@ -1,17 +1,17 @@
-FROM php:7.3-fpm
+FROM php:7.4-fpm
 
 RUN apt-get update
 
 RUN apt-get install -y \
 	git unzip wget zip curl mlocate \
-	libmcrypt-dev libicu-dev libpcre3-dev libicu-dev \
+	libicu-dev libpcre3-dev libicu-dev \
 	build-essential chrpath libssl-dev \
 	libxft-dev libfreetype6 libfreetype6-dev \
 	libpng-dev libjpeg62-turbo-dev \
 	libfontconfig1 libfontconfig1-dev libzip-dev libldap2-dev
 
-RUN pecl install mcrypt-1.0.2 && \
-	docker-php-ext-enable mcrypt
+RUN pecl install xxtea-1.0.11 && \
+	docker-php-ext-enable xxtea
 
 RUN docker-php-ext-configure intl && \
     docker-php-ext-configure ldap && \
diff --git a/.docker/release/Dockerfile b/.docker/release/Dockerfile
index ebda05a40..76816a3e8 100644
--- a/.docker/release/Dockerfile
+++ b/.docker/release/Dockerfile
@@ -1,5 +1,5 @@
 # Inspired by the original Rainloop dockerfile from youtous on GitLab
-FROM php:7.3-fpm-buster
+FROM php:7.4-fpm-buster
 
 ARG FILES_ZIP
 LABEL org.label-schema.description="SnappyMail webmail client image using nginx, php-fpm based on Debian Buster"
@@ -15,7 +15,7 @@ RUN mkdir -p /usr/share/man/man1/ /usr/share/man/man3/ /usr/share/man/man7/ && \
         apt-transport-https gnupg openssl wget curl ca-certificates nginx supervisor sudo \
         unzip libzip-dev libxml2-dev libldb-dev libldap2-dev \
         sqlite3 libsqlite3-dev libsqlite3-0 libpq-dev postgresql-client mariadb-client logrotate \
-        zip mlocate libmcrypt-dev libpcre3-dev libicu-dev \
+        zip mlocate libpcre3-dev libicu-dev \
         build-essential chrpath libssl-dev \
         libxft-dev libfreetype6 libfreetype6-dev \
         libpng-dev libjpeg62-turbo-dev \
@@ -45,4 +45,4 @@ COPY files /
 RUN chmod +x /entrypoint.sh && chmod +x /logrotate-loop.sh
 VOLUME /snappymail/data
 EXPOSE 8888
-CMD ["/entrypoint.sh"]
\ No newline at end of file
+CMD ["/entrypoint.sh"]