This was on Arch Linux, version 1.5.0:

$ pacman -Qs xmlstarlet
local/xmlstarlet 1.5.0-1
A set of tools to transform, query, validate, and edit XML documents
$ xmlstarlet --version
1.5.0
compiled against libxml2 2.9.1, linked with 20902
compiled against libxslt 1.1.28, linked with 10128