A new version of tsschecker was created by @tihmstar and it finally supports proper SHSH2 Tickets saving for future downgrade of iPhone 7 and not only. All blobs saved until this version with any tool are NOT valid, but according to @tihmstar, you should not trash them as they might still be useful in the future (if you saved the 10.1.1 ones).
Why saving iOS 10.2 tickets?
Luca Todesco (the man behind the iOS 10.1.1 Yalu Jailbreak) reiterated a previous warning he gave on his twitter about iOS 10.2 blobs you must save with the new tsschecker, he recommended everyone to save them and keep them safe, and avoid upgrading to iOS 10.2.1 in the future.
Downgrades are currently possible with SHSH2 blobs, and were already demoed by a lot of people. Saving your iOS 10.2 is not only useful if you are looking to Jailbreak, but also for future iCloud Bypass. You don't need your device to be activated to be able to save them so, go ahead.
Latest tsschecker: https://goo.gl/8aFHN4
iPhone SE iOS 10.1.1 Jailbreak: https://youtu.be/5EMB4XFqy-w
i am just reiterating a previous warning; no 10.2 jailbreak is planned but still avoid 10.2.1, and save 10.2 blobs
— qwertyoruiop (@qwertyoruiopz) January 5, 2017