Medium Description
Before I break my Fisheye installation by upgrading Mercurial (again), are you testing the latest Mercurial release as a matter of course?
For future reference, Mercurial releases a new major release every three months, per:
http://mercurial.selenic.com/wiki/TimeBasedReleasePlan
It would be helpful if Atlassian performed these compatibility tests as a matter of course, rather than relying on customers to prod you to keep up. 
Thanks
Updating with the stacktrace:
2013-07-03 18:44:20,690 ERROR [InitialPinger1 Dragons] fisheye BaseRepositoryScanner-handleSlurpException - Problem processing revisions from repo Dragons due to class com.cenqua.fisheye.rep.RepositoryClientException - com.atlassian.fisheye.dvcs.handler.DvcsProcessException: Error while communicating with VCS: ** Unknown exception encountered with possibly-broken third-party extension felog
** which supports versions unknown of Mercurial.
** Please disable felog and try your action again.
** If that fixes the bug please report it to the extension author.
** Python 2.7.2 (default, Oct 11 2012, 20:14:37) [GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)]
** Mercurial Distributed SCM (version 2.6+20130507)
** Extensions loaded: felog
Traceback (most recent call last):
File "/usr/local/bin/hg", line 38, in <module>
mercurial.dispatch.run()
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 28, in run
sys.exit((dispatch(request(sys.argv[1:])) or 0) & 255)
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 65, in dispatch
return _runcatch(req)
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 88, in _runcatch
return _dispatch(req)
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 771, in _dispatch
cmdpats, cmdoptions)
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 540, in runcommand
ret = _runcommand(ui, options, cmd, d)
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 866, in _runcommand
return checkargs()
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 837, in checkargs
return cmdfunc()
File "/Library/Python/2.7/site-packages/mercurial/dispatch.py", line 766, in <lambda>
d = lambda: util.checksignature(func)(ui, *args, **cmdoptions)
File "/Library/Python/2.7/site-packages/mercurial/util.py", line 506, in check
return func(*args, **kwargs)
File "/Users/luziamendes/fisheye/fecru-2.10.0/python/hg/hgfelog/hgfelog.py", line 95, in felog
felognode(ui, repo, repo[r], **opts)
File "/Users/luziamendes/fisheye/fecru-2.10.0/python/hg/hgfelog/hgfelog.py", line 121, in felognode
diffParent(ui, repo, ctx, commitState, f, opts.get('patch'), opts.get('converted'), opts.get('merges'), opts.get('changesets'))
File "/Users/luziamendes/fisheye/fecru-2.10.0/python/hg/hgfelog/hgfelog.py", line 136, in diffParent
processPath(ui, repo, ctx, commitState, format, diffs, svnConversion, f)
File "/Users/luziamendes/fisheye/fecru-2.10.0/python/hg/hgfelog/hgfelog.py", line 161, in processPath
state.diff(ui, format['diff'], repo, ctx)
File "/Users/luziamendes/fisheye/fecru-2.10.0/python/hg/hgfelog/hgfelog.py", line 459, in diff
writePrefixed(ui, prefix, mdiff.unidiff(aFileData, aFileDate, bFileData, bFileDate, aFileName, bFileName, None, diffopts))
TypeError: unidiff() takes at most 7 arguments (8 given)
