diff --git a/10.0/apache/Dockerfile b/10.0/apache/Dockerfile
index 570aef6c..ed183857 100644
--- a/10.0/apache/Dockerfile
+++ b/10.0/apache/Dockerfile
@@ -13,12 +13,15 @@ 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 b60b57f2..fc781c0e 100644
--- a/10.0/fpm/Dockerfile
+++ b/10.0/fpm/Dockerfile
@@ -13,12 +13,15 @@ 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 3ba14c71..32a710d0 100644
--- a/11.0/apache/Dockerfile
+++ b/11.0/apache/Dockerfile
@@ -13,12 +13,15 @@ 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 0b86d169..7d8e13da 100644
--- a/11.0/fpm/Dockerfile
+++ b/11.0/fpm/Dockerfile
@@ -13,12 +13,15 @@ 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 07ede264..c2ce4db4 100644
--- a/9.0/apache/Dockerfile
+++ b/9.0/apache/Dockerfile
@@ -13,12 +13,15 @@ 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 fd82cb3a..c8889783 100644
--- a/9.0/fpm/Dockerfile
+++ b/9.0/fpm/Dockerfile
@@ -13,12 +13,15 @@ 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 345009d2..a12963bd 100644
--- a/Dockerfile-php7.template
+++ b/Dockerfile-php7.template
@@ -13,12 +13,15 @@ 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 24ef5e9c..a3a483ad 100644
--- a/Dockerfile.template
+++ b/Dockerfile.template
@@ -13,12 +13,15 @@ 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