Well I've made the effort and things are now apparently running Ok with 2.4. As was expected the web pages were full of error messages until I added SSILegacyExprParser On to the configuration file.
Re nginx - I don't really care what I'm running. I use the (private) local website to add new content/features where I check that it runs and that there are no syntax errors. Once I'm happy that all looks ok and functions as it should I upload it to the public web site on my hosting company's servers. My only criteria is that my local server matches the behaviour of the hosting company's server - that way all my mistakes are hopefully made in private.
Anyway, back to the start, if apache2.tcz does produce segmentation faults with the latest releases should it be even appear in the app browser?