You can use these phrases to convey similar meanings:
Comparative:
* More modern: This is a more general way to describe something as relatively modern.
* Newer: This specifically refers to something that is newer in time.
* More up-to-date: This emphasizes that something is current and relevant.
* More contemporary: This refers to something that is typical of the present time.
Superlative:
* Most modern: This is the most general way to describe something as the most modern.
* Newest: This specifically refers to something that is the newest in time.
* Most up-to-date: This emphasizes that something is the most current and relevant.
* Most contemporary: This refers to something that is the most typical of the present time.
It's important to choose the most appropriate phrase based on the context and the specific meaning you want to convey.