Following their previous revision, today Sony pushed live a PS3 System Software / Firmware 4.91 Update which 'improves system performance' yet again for those still in the PS3 Scene with further details on renewing the console's Blu-ray player encryption key in the official changelog below. 
As always, it's NEVER a wise idea to update PlayStation Firmware in order to make use of such things as PS3 Custom Firmware (CFW), PS3 Downgrading, PS3 Homebrew, PS3 Jailbreaking, etc for those in the PS3Scene.
Download: PS3 Firmware 4.91 (EU) Update / PS3 Firmware 4.91 (US) Update / PS3 Firmware 4.91 (AU/NZ) Update / PS3 Firmware 4.91 (JP) Update
And from Sony's official page: PS3 system software features
Version 4.91
An update to the PS3 system software was released on 02/27/24.
To download the update, you need a minimum of 200MB of free space on either the PS3 Hard Disk Drive (System Update) or on removable storage media (PC Update).
Always update your PS3 system to the latest version of the system software. By updating, you can enjoy additional features, improved usability, and enhanced security.
Please note, to play Blu-ray discs, your PS3 system needs a renewed Blu-ray player encryption key. Please update your PS3 system software to the latest version to renew the Blu-ray player encryption key.
As the PlayStation 3 (PS3) Scene Forums are closed / read-only for archival purposes, this is posted in the PlayStation 4 (PS4) Scene Forums and is also closed for new comments / replies. 
As always, it's NEVER a wise idea to update PlayStation Firmware in order to make use of such things as PS3 Custom Firmware (CFW), PS3 Downgrading, PS3 Homebrew, PS3 Jailbreaking, etc for those in the PS3Scene.Download: PS3 Firmware 4.91 (EU) Update / PS3 Firmware 4.91 (US) Update / PS3 Firmware 4.91 (AU/NZ) Update / PS3 Firmware 4.91 (JP) Update
And from Sony's official page: PS3 system software features
Version 4.91
- This system software update improves system performance.
An update to the PS3 system software was released on 02/27/24.
To download the update, you need a minimum of 200MB of free space on either the PS3 Hard Disk Drive (System Update) or on removable storage media (PC Update).
Always update your PS3 system to the latest version of the system software. By updating, you can enjoy additional features, improved usability, and enhanced security.
Please note, to play Blu-ray discs, your PS3 system needs a renewed Blu-ray player encryption key. Please update your PS3 system software to the latest version to renew the Blu-ray player encryption key. As the PlayStation 3 (PS3) Scene Forums are closed / read-only for archival purposes, this is posted in the PlayStation 4 (PS4) Scene Forums and is also closed for new comments / replies. 
