What is cfg file syntax for v8i VERSION number?

This should be an easy one, but I can't find the answer anywhere.

What is the correct syntax for specifying the V8i version in a config file?

For example, for version XM in the config I say: %elif defined  (_VERSION89)

What is the number for version 8.11? I tried _VERSION811, but that doesn't work.

Thanks,  Karen