IRule no longer working after upgrade from 10.2.4 to 11.4.1

What you'll find in v11 systems is that objects are now prefaced by the container partitions that they're in. If you were to log the above PROFILE command, you'd probably see something like this:

/Common/my-clientssl-profile

One of the best ways to get around this then is to simply strip that partition value out of the string. For example, if you know the profile is in the Common partition:

[string map -nocase {"/Common/" ""} [PROFILE::clientssl name]]

will remove the /Common/ portion of the string and leave behind just the profile name.