Mailchimp extension compatibility with CiviCRM 4.7
In general, extensions marked as compatible with 4.6 will usually work with 4.7 as well. It may be that the extension author just hasn't had a chance to test it and tag a new release for 4.7. I recommend you:


Install the extension and try it out
Notice if it works correctly or not. Gather specific details of anything that may be amiss.
File an issue on the extension's github page noting your findings so that the maintainer can either fix the bugs or else tag a release as-is for 4.7.