Just a week after launching the third macOS Sierra 10.12.1 beta, Apple is now rolling out the fourth beta version of the upcoming macOS Sierra update that is said to be officially released alongside the new MacBook Pro. 

According to MacRumors, Apple seeded the fourth beta to developers and public beta testers this Tuesday for further testing ahead of the final OS update's release to the public. 

The new beta is reportedly filled with bug fixes and implementations that would enhance under-the-hood performance. The beta also is expected to address all of the issues uncovered since macOS Sierra was officially rolled out. 

The fourth macOS Sierra 10.12.1 beta version could be the last one before the final update is rolled out. It is available for download from the Apple Developer Center or via the Software Update option in the Mac App Store. Only those who are enrolled in Apple’s beta testing program can download and test out the new beta with build code 16B2548a.

AppleInsider reports the final macOS Sierra 10.12.1 could ship on the next-generation MacBook Pro later this month. The software update is said to be quite essential since it provides support for the OLED touch bar that’s rumored to be part of the redesigned MacBook Pro. 

The OLED display bar is rumored to be placed atop the keyboard of the MacBook device, replacing the topmost physical function keys found in the previous iterations of the Apple laptop.

Based on the first three beta versions, the final macOS Sierra 10.12.1 update would also have Photos support for the iPhone 7 Plus-captured images using the new Portrait mode that is rolling out with iOS 10.1. 

 If recent rumors are to be believed, Apple is unveiling its new MacBook Pro along with a new MacBook Air in a few weeks, just before the month of October ends. While the MacBook Pro is rumored to be a complete redesign, the new MacBook Air could just be a refresh of its predecessor.