As mentioned in the new features section the following properties having been transformed in configurations, so they are no longer available in the properties files:
session.timeout.auto.extendsession.timeout.auto.extend.offset
Release Notes
This section contains information about breaking changes in out-of-the-box DXP features and capabilities. For breaking changes or internal code, please check this link.
The configuration sections in Utility Pages are not enabled, as the other pages, due to their use being more restricted. The implementation of these settings should occur by analyzing each case.