To be precise:
Get the list of all users in the old system, then find the PHP version:
/usr/bin/cl-selector --current=php --user=USERNAME will retrieve PHP version set for a particular user. The script gets the path from /var/cagefs/USERID/USERNAME/etc/cl.sel/php symlink, compares it with contents of /etc/cl.selector/selector.conf file and if path is valid, prints out the current interpreter version.
In the destination server, repeat in reverse, setting PHP version for all usernames
/usr/bin/cl-selector --select=php --version=5.3 --user=USERNAME sets the current PHP version for particular user by creating symlink in /var/cagefs/USERID/USERNAME/etc/cl.selector directory. All old symlinks are removed, and new symlinks are set.
For bulk information retrieval and updates regex commands are your friends.