The current version 2.5 is from September 2014, which is almost 8 years
old now. The new version 3.19.0 is from November 2017, which is still
almost 5 years old, but is a step forward towards eventually using the
most recent version. Note that we currently can't update any further;
see #11802 for the details.
Fortunately using this newer version only required a few changes:
- The `ttx` output regexes needed updating to ignore comments that `ttx`
now puts after some XML nodes (`<!-- ... -->` and `/* ... */`).
- The `ttx` invocation now explicitly uses `python2` (except on Windows
where this alias doesn't exist) since otherwise the font tests can't
be run on modern systems anymore given that `python` is nowadays an
alias for `python3`, and it now points at the new location of the
`ttx.py` file since the `Tools` folder got removed.
- The note about needing a 32-bit Python 2.6 version is dropped since
it's obsolete: this version (and also the existing one already) work
just fine on a 64-bit Python 2.7 as well.
