The new update will be available via FOTA and through LG Bridge Upgrade. This is still a Lollipop OS firmware with Some bug fixes and latest security patch.
The Stock KDZ firmware for LG Leon H345 i also available for download now from LG offical website;
Download T-mobile LG Leon H345 Stock KDZ Firmware:
You’d better download and save a copy of this firmware onto your PC. In case that you bricked your LG Leon.
Want to check LG H345 software Update History? Check LG Open source code page for LG H345 model here.
To resotre your device back to stock, You may need LG UP tool. We have shared with your several different verison of the LG UP TOOL and latest usb drivers and DLL files need for LG UP for LG H345 model.
If you experieneced any issues with your LG H345, Please Let us Know.