Call for Testing: UBports Installer 0.7.4-beta

[NeoTheThird]

This maintenance release improves some error handling and improves the process of re-connecting to devices if the cable is unreliable.

• https://github.com/ubports/ubports-installer/releases/tag/0.7.3-beta
• https://ubports.open-cuts.org/build/5fb3b7169702a600079dcf6e

[NeoTheThird]

Sorry for the quick iterations, here's yet another one:

• https://github.com/ubports/ubports-installer/releases/tag/0.7.4-beta
• https://ubports.open-cuts.org/build/5fb3f18b9702a600079dcfe8

Due to time constraints, we had to squeeze another minor thing in.