PlayStation 5 Compatibility Is To Be Added To PS4 Titles Starting From July; Updates To Existing Titles Are “Strongly Recommended”

All PlayStation 4 titles beginning July 13th will have to come with full PlayStation 5 compatibility.

A new report from Eurogamer confirms that it will be up to the developer to make sure all upcoming PlayStation 4 titles submitted to Sony from July 13th run on PlayStation 5 as well. A PlayStation 4 game can be deemed fully playable on PlayStation 5 only if it provides the same features as when running on current-generation hardware.

Sony Making Games That “Can Only be Enjoyed on PS5,” Xbox Crossgen Approach Not for Them

Developer documentation - released on PlayStation's internal Partner website and seen by Eurogamer - details an option developers must check to state their game has been tested for compatibility with PS5 hardware. This option was added at the end of April in a new version of Sony's PS4 software developer kit.
Sony has told developers it will contact them individually with details on how to test PS5 compatibility, in the order of their various projects' release.

Any game submitted to Sony before July 13th, however, will not be required to have PlayStation 5 compatibility, with the console manufacturer only recommending an update.

If a game was originally submitted to Sony before 13th July 2020, any new patch or remaster after that date would not require PS5 compatibility, but it would be "strongly recommended".
If a game was originally submitted to Sony after 13th July 2020, any future patch or remaster to that game would need to keep PS5 compatibility. Once a game is PS5 compatible, it must stay so.

There is still a lot we do not know about PlayStation 5 backward compatibility. Games will supposedly benefit from higher and more stable frame rates and even higher resolutions, but it not yet know if the improvements will be on the same level as the ones promised by the Xbox Series X backward compatibility, which will bring HDR support for all games as well as doubled frame rates for select titles.

The PlayStation 5 launches later this year worldwide. A final release date has yet to be confirmed.