Please note that this release includes a change in Synapse to use Redis
as a cache ─ as well as a pub/sub mechanism.
This release also changes the callback URI for OpenID Connect (OIDC)
identity providers. If your server is configured to use single sign-on
via an OIDC/OAuth2 IdP, you may need to make configuration changes.
This release also changes escaping of variables in the HTML templates
for SSO or email notifications.