Server caching (as default) maintains the previous behaviour.
We should, at some point, add a server side configuration option to enable/disable caching.

Saying that, I'm actually having 2nd thoughts as to whether client should pass a flag as a hint (optionally).
If no flag is sent, the server configuration defines the caching (default) behaviour.

The client can send IFEnocache or IFEcache (or neither) - the server is at liberty to ignore the hint though.
It may make sense for some files that are expected to be request often to be cached in some circumstances, e.g. TLK key parts.

@ghalliday  - agree/disagree?