We started work on integrating Saxon 9.7 some time ago and we had many
interactions with Saxonica but unfortunately we were not able to update
the internal Saxon engine used in oXygen to Saxon 9.7.
However, in parallel with this development, we started to work on
exposing a plugin API that allows integrating an XSLT and XQuery engine
as an integrated external processor and we implemented those extension
points in a plugin that brings Saxon 9.7 validation and transformation
support into oXygen.
Then, you should be able to see "Saxon-EE 22.214.171.124 (External)" as one of
the XSLT or XQuery engine options for validation or transformation.
For example, to default XSLT 3.0 validation to Saxon 9.7, you can go to
Options->Preferences -- XML / XSLT-FO-XQuery / XSLT and select the
"Saxon-EE 126.96.36.199 (External)" option as the validation engine for XSLT 3.0.
One can say that not being able to finalize the 9.7 integration has its
good parts as well, because this new plugin API support will allow
having plugins for all versions of Saxon, so it will a lot easier to
test against a specific Saxon version from within oXygen as these are
more integrated than just configuring an external engine with a command