Fallback in ParserOptions::newCanonical() hard deprecated since 1.35[1]
Fallback in ParserOptions::__construct() hard deprecated since 1.36[2]
Both fallbacks can be removed now (1.37)
[1] https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+/44945be0a539ebd687db3d71d1d5736d0821f9bf
[2] https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+/25db391d535b5b9c6f19c4ff507efe3040b54f4f