A few hints to get you going:
- Please back up your models and settings before upgrading so that you can go back to 2.0 should you not like 2.1 or find issues that make it unsuitable for you. Use the "backup radio to file" companion feature for this to have an exact copy of what was on your radio.
- As a new major release a new data format has been put in place, existing models and settings will be upgraded keeping things compatible as much as possible, but not everything can be converted. Only OpenTX 2.0 settings can be upgraded by the radio, if you currently run an even older firmware version you have to either go through 2.0 first before flashing 2.1, or do the conversion within companion. It is absolutely necessary to go through all your models after the upgrade, check they are operating properly and fix the potential issues before flying or applying motor power.
- Coming from 2.0 you'll notably lose EVERY telemetry-related setting, that will need to be reconfigured from scratch. Sensor configuration, alarms, custom telemetry screens, everything.
- This is a .0 release. A lot of testing has been done by developers and beta testers, but inevitably some issues only pop up with large scale use and particular use cases. Issues that have been found and are being worked on for 2.1.1 can be found here. If you see something that would affect you in that list hold off for the next release, if you're not very adverturous hold off for a few releases until things are well ironed out.
- An existing issue with 2.1.0 affects model conversion (receiver number is lost for models using a DIY DSM module), you'll have to reenter them manually, or either wait until 2.1.1 is out and fixes it to convert your models or reload your 2.0 backup then to re-run the "fixed" conversion (that would of course mean losing all changes you'd have made on 2.1 since).
- Voice packs have changed. You need to download and copy the new 2.1 voice packs to your radio's SD card to have correct voice announcements. Changes are mostly on telemetry units, so if you hear wrong units your problem is likely there.
- 2.0 lua telemetry scrips will not work anymore, they need to be updated (see here and the next 2 posts for some info). They are also now selected differently, the modelname\telemX.lua method is obsolete, it is replaced by setting the type of a telemetry screen to Script and choosing the appropriate script from those placed in the SCRIPTS\TELEMETRY folder of the SD card.
- There is no 2.1-specific documentation as of now besides this thread, the telemetry system preview thread, and the 2.1 thread on RCGroups where users of the beta versions have been gathering some info.
You can get it from the downloads section of http://www.open-tx.org.
Due to the major differences and to avoid confusing users major releases like this are not offered as an "upgrade" anymore, they are a separate package that you install separately from previous versions. You can thus install and use Companion 2.0 and 2.1 simultaneously on your PC, and for example manage a radio on 2.0 and another on 2.1 without issues. 2.0 will stay available and even be maintained for a while (bug fixes only) for users who don't want to make the jump but prefer to enjoy a stable version.
I'll try to come back and add things here when I think of something useful, don't hesitate to add yours below.