Which version of libxml2 and libxslt should I use or require?
It really depends on your application, but the rule of thumb is: more recent versions contain less bugs and provide more features. • Do not use libxml2 2.6.27 if you want to use XPath (including XSLT). You will get crashes when XPath errors occur during the evaluation (e.g. for unknown functions). This happens inside the evaluation call to libxml2, so there is nothing that lxml can do about it. • Try to use versions of both libraries that were released together. At least the libxml2 version should not be older than the libxslt version. • If you use XML Schema or Schematron which are still under development, the most recent version of libxml2 is usually a good bet. • The same applies to XPath, where a substantial number of bugs and memory leaks were fixed over time. If you encounter crashes or memory leaks in XPath applications, try a more recent version of libxml2. • For parsing and fixing broken HTML, lxml requires at least libxml2 2.6.21. • For the normal tree handling, however, any
