As usual, Wt 4.8.1 is a patch release, but we also added a document clarifying our policy on which minimum versions of libraries Wt requires. You can find this document in Wt’s source tree at doc/MinimumDependencyVersions.md. Check the release notes for more info.
Here are the links:
Wt 4.8.1 (C++): download wt-4.8.1.tar.gz (release notes)
JWt 4.8.1 (Java): download jwt-4.8.1.zip (release notes)
Binary builds for Windows are available on the GitHub releases page.