[Bug] Ramiel says that the iOS 15.x beta is not supported when using it with a non-beta release

[XboxOneSogie720]

Describe the bug
I just used Divise on iOS 14.3, and I was told to use Ramiel to dual boot into iOS 15.0. I downloaded an iOS 15.0 release from ipsw.me, and tried to use it when Ramiel said that the betas were not supported. It said this while parsing BuildManifest.

To Reproduce
Steps to reproduce the behavior:

1. Go to Cydia/Sileo/Zebra/whatever, download and install Divise, dual boot to iOS 15.x, follow the instructions on screen. After it's done, pwn with gaster (Ramiel pwning doesn't work for me) and open Ramiel.
2. Click on Advanced, check Boot Dual Boot iOS (or something like that, I don't have Ramiel open to put the exact words), type the disk identifier that Divise gave you before you reboot, go to next screen, then hit boot in Ramiel.
3. Scroll down to the version of iOS you installed on Divise, in my case, 15.0
4. See error

Expected behavior
Ramiel boots the iPhone into iOS 15.0 to the specified disk identifier

Desktop (please complete the following information):

• macOS Version: macOS Catalina 10.15.7
• Machine Model: MacBook Pro (13-inch, Mid 2012)
  Ramiel_Error_Log_1.12.AM.txt

iOS/iPadOS Device(please complete the following information):

• Model: iPhone8,4
• iOS Version Being Booted: iOS 15.0
• Dualbooted: Yes