= Added iss parameter to OAuth 2.0/OpenID Connect Authentication Response

RFC 9207 OAuth 2.0 Authorization Server Issuer Identification specification adds the parameter `iss` in the OAuth 2.0/OpenID Connect Authentication Response for realizing secure authorization responses.

In past releases, we did not have this parameter, but now {project_name} adds this parameter by default, as required by the specification.

However, some OpenID Connect / OAuth2 adapters, and especially older {project_name} adapters, may have issues with this new parameter.

For example, the parameter will be always present in the browser URL after successful authentication to the client application.
In these cases, it may be useful to disable adding the `iss` parameter to the authentication response. This can be done
for the particular client in the {project_name} Admin console, in client details in the section with `OpenID Connect Compatibility Modes`,
described in <<_compatibility_with_older_adapters>>. Dedicated `Exclude Issuer From Authentication Response` switch exists,
which can be turned on to prevent adding the `iss` parameter to the authentication response.

= Wildcard characters handling

JPA allows wildcards `%` and `_` when searching, while other providers like LDAP allow only `*`.
As `*` is a natural wildcard character in LDAP, it works in all places, while with JPA it only
worked at the beginning and the end of the search string. Starting with this release the only
wildcard character is `*` which work consistently across all providers in all places in the search
string. All special characters in a specific provider like `%` and `_` for JPA are escaped. For exact
search, with added quotes e.g. `"w*ord"`, the behavior remains the same as in previous releases.

= Language files for themes default to UTF-8 encoding

This release now follows the standard mechanisms of Java and later, which assumes resource bundle files to be encoded in UTF-8.

Previous versions of Keycloak supported specifying the encoding in the first line with a comment like `# encoding: UTF-8`, which is no longer supported and is ignored.

Message properties files for themes are now read in UTF-8 encoding, with an automatic fallback to ISO-8859-1 encoding.
If you are using a different encoding, convert the files to UTF-8.

