Don't Install iOS 13.4 If You're Nervous About Bugs
If you're having an excellent experience on iOS 13.3.1, iOS 13.3, iOS 13.2.3, iOS 13.2.2, iOS 13.2, iOS 13.1.3, iOS 13.1.2, iOS 13.1.1, iOS 13.1, iOS 13.0, or iOS 12 and iOS 13.4's changes don't blow you away and/or you're nervous about it potentially hurting your iPhone's performance, you might want to wait.
The iOS 13.4 update brings bug fixes with it, but the update has also brought a collection of problems to the iPhone.
The current list of iOS 13 problems includes some familiar faces: abnormal battery drain, issues with first and third-party applications, Bluetooth problems, problems with Wi-Fi, issues with cellular data, installation issues, lag, random reboots, issues with Face ID, and problems with Touch ID. There's also a security issue with VPN's.
If these issues concern you, you might want to wait for Apple's next version of iOS 13.