In 2.2.14, mod_deflate doesn't change ETag when it compresses output (... about which http://redbot.org complains: ETag is supposed to change between different representations). In 2.2.11 on the other hand, mod_deflate does change ETag, but in a bad way: Before compression: "a2c00a-ef7-486bb5bae5280" After compression: "a2c00a-ef7-486bb5bae5280"-gzip ... but it really should be: "a2c00a-ef7-486bb5bae5280-gzip" (ETag is supposed to be a quoted string, so there shouldn't be parts of the string outside of quotes...)
Note that the original fix included in 2.2.8 introduced another problem: https://issues.apache.org/bugzilla/show_bug.cgi?id=45023 https://issues.apache.org/bugzilla/show_bug.cgi?id=47253 so it got reverted before version 2.2.12: http://svn.apache.org/viewvc?view=revision&revision=761835 The whole problem is discussed in BZ 39727 and http://marc.info/?t=116545219400003&r=1&w=2 http://marc.info/?t=118821803900003&r=1&w=2 http://marc.info/?t=119141796500004&r=1&w=2 *** This bug has been marked as a duplicate of bug 39727 ***