There have been two new releases in the last month or so in Santuario / XML Security.
XML Security (Java) 1.4.4 was released in November. This release contains some enhancements to the resolver API's. It also fixes some longstanding issues with interned Strings, as well as a number of bug fixes.
XML Security (C++) 1.6.0 was released in December. This release provides many bug fixes and a partial implementation of XML Signature 1.1 features, including ECDSA signatures.
You can download both releases here.