Internal Changes ---------------- - Update federation routing logic to check .well-known before SRV ([\#4539](https://github.com/matrix-org/synapse/issues/4539)) - Improve performance of handling servers with invalid .well-known ([\#4542](https://github.com/matrix-org/synapse/issues/4542)) - Treat an invalid .well-known file the same as an absent one ([\#4544](https://github.com/matrix-org/synapse/issues/4544))