CWP: How to upgrade from RoundCube Mail Version 1.2.3 to RoundCube Mail Version 1.3.8

The new Version of Roundcube 1.3 have clear Interface with modern look also in this version some major security holes were fixed. It is recommended to update the roundcube to latest version. Under latest version you can also configure calendar plugin faultlessly which are available on roundcube plugins site.

PHP Configuration
As any other PHP application some of its aspects depend on PHP settings. You should use php.ini or .htaccess (Apache module) or .user.ini (CGI/FastCGI SAPI) depending on your server setup. Roundcube when running will check most critical settings, try to set them and let you know if something's wrong. Here's a minimal list of settings that you might need to use (with suggested value):

# vi /usr/local/php/php.ini
# vi /usr/local/cwp/php71/php.ini 

• Memory limit: memory_limit=64M,
• Options that control logging: display_errors=Off, log_errors=On, error_log=logs/errors.log,
• Options that control file uploads (e.g. max attachment size): upload_max_filesize=5M, post_max_size=6M,
• Options that are not compatible with Roundcube: zlib.output_compression=Off, suhosin.session.encrypt=Off, session.auto_start=Off,
• Options that control session behaviour: session.gc_maxlifetime=21600, session.gc_divisor=500, session.gc_probability=1.

1.Login to SSH (Using putty)
2.Backup old roundcube configuration.

# cd /usr/local/cwpsrv/var/services
# cp -rvf roundcube roundcube.bak 

Download latest version of roundcube.

# cd /usr/local/src/
# rm -rf roundcube*
# wget https://github.com/roundcube/roundcubemail/releases/download/1.3.8/roundcubemail-1.3.8-complete.tar.gz

# wget https://roundcube.net/download/pubkey.asc
# wget https://github.com/roundcube/roundcubemail/releases/download/1.3.8/roundcubemail-1.3.8-complete.tar.gz.asc
# gpg --verify roundcubemail-1.3.8-complete.tar.gz{.asc,}  OR
# gpg --verify roundcubemail-1.3.8-complete.tar.gz.asc

# tar zxvf roundcubemail-1.3.8-complete.tar.gz 
# cd roundcubemail-1.3.8/ 

Proceed with the installation

# bin/installto.sh /usr/local/cwpsrv/var/services/roundcube 

Copy composer.json from roundcube.bak into roundcube

# chown -R cwpsvc:cwpsvc /usr/local/cwpsrv/var/services/roundcube/
# cd /usr/local/cwpsrv/var/services/roundcube/
# php composer.phar update --no-dev   or 
# php composer.phar update  ; if you get any error then try
# php composer.phar install ; again error then try
# php composer.phar install --no-dev

Now enable the roundcube installer  by follow the Link and check the configuration file.

Helpful Link:
Link 1