It is possible still.
It might be worth noting that if testing with the samples from MIP SDK the Trigger Generic Event sample will work while theTrigger Generic Event Stream will not work on XProtect Professional, the latter sample will work with c-code servers only (XProtect Corporate, Expert and Plus products (Including Professional+).
In XProtect Professional generic events are ready for use while in XProtect Professional+ you need a small configurations step before you can use it: Use Management Client->Tools->Options->Generic Event tab to configure.