Your question doesn't make sense.
.fp7 is the file format used for filemaker 7 through filemaker 11. Filemaker 12 introduced the .fmp12 format, used from version 12 through the current version 14.
So yes, filemaker server 11 is indeed compatible with hosting .fp7 files.
HOWEVER, the features that are compatible INSIDE of the file are based on what version you HOST with, and more importantly, what version you CONNECT with.
EG, hosting on v11 will not magically let a filemaker pro 8 user get all of the features released in 9,10,11 as well. They will be limited to the features of 8.
It's always recommend to host on the same version that your connecting users have for this reason.
Almost all of this is a mute point though, since FM11 is so outdated and unsupported, and you should really upgrade to 14 to get the latest compatibility and updates.