Comment 11 for bug 802942

I guess that Cairo is part of the Gecko engine which then is used by firefox and thunderbird.

My Firefox 40.0.3 comes shipped with Gecko/20100101 according to about:support tab:

Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:40.0) Gecko/20100101 Firefox/40.0

which basically explains why cairo is so old (as said, cairo 1.9.5 dates to ~2009/2010).

To sum it up, either firefox needs to get a recent gecko engine and/or the gecko engine used for firefox needs to have a recent cairo version.

If that does not solve the problem (maybe mozilla just will not fix it for years), then cups-filters comes into play.

Same applies for thunderbird.