diff --git a/10.0/apache/Dockerfile b/10.0/apache/Dockerfile
index c7c580d8..8b8c0441 100644
--- a/10.0/apache/Dockerfile
+++ b/10.0/apache/Dockerfile
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/10.0/fpm/Dockerfile b/10.0/fpm/Dockerfile
index cdb7a346..5e02995f 100644
--- a/10.0/fpm/Dockerfile
+++ b/10.0/fpm/Dockerfile
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/11.0/apache/Dockerfile b/11.0/apache/Dockerfile
index e801a80e..06e09051 100644
--- a/11.0/apache/Dockerfile
+++ b/11.0/apache/Dockerfile
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysqli opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysqli opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/11.0/fpm/Dockerfile b/11.0/fpm/Dockerfile
index ea6f93ae..cbd0ba7f 100644
--- a/11.0/fpm/Dockerfile
+++ b/11.0/fpm/Dockerfile
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysqli opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysqli opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/9.0/apache/Dockerfile b/9.0/apache/Dockerfile
index b5f77401..72714b3b 100644
--- a/9.0/apache/Dockerfile
+++ b/9.0/apache/Dockerfile
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/9.0/fpm/Dockerfile b/9.0/fpm/Dockerfile
index da3911df..9a4df2fb 100644
--- a/9.0/fpm/Dockerfile
+++ b/9.0/fpm/Dockerfile
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/Dockerfile-php7.template b/Dockerfile-php7.template
index 6dd989a5..6c50b6d9 100644
--- a/Dockerfile-php7.template
+++ b/Dockerfile-php7.template
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysqli opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysqli opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php
diff --git a/Dockerfile.template b/Dockerfile.template
index 3d713793..dafc3d7f 100644
--- a/Dockerfile.template
+++ b/Dockerfile.template
@@ -12,12 +12,15 @@ RUN apt-get update && apt-get install -y \
   libpng12-dev \
   libpq-dev \
   libxml2-dev \
+  libc-client-dev \
+  libkrb5-dev \
   && rm -rf /var/lib/apt/lists/*
 
 # https://docs.nextcloud.com/server/9/admin_manual/installation/source_installation.html
 RUN docker-php-ext-configure gd --with-png-dir=/usr --with-jpeg-dir=/usr \
   && docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu \
-  && docker-php-ext-install gd exif intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
+  && docker-php-ext-configure imap --with-imap-ssl --with-kerberos \
+  && docker-php-ext-install gd exif imap intl mbstring mcrypt ldap mysql opcache pdo_mysql pdo_pgsql pgsql zip
 
 # set recommended PHP.ini settings
 # see https://secure.php.net/manual/en/opcache.installation.php