Hello, everyone. Here is what I have in my phone:

And I saw this video: How To: Motorola Defy/Defy+ Jelly Bean (4.1.1) Installation Guide - YouTube
I am wondering if it is safe to move from GB to JB? And if it is possible to go back if for some reason it is not stable? By the way, the version mentioned on the video of JB is the stock version, or custom version? Because if I am correct; the stock versions are not downgradeable, but custom ROMs are downgradeable. Is that all right?
If yes, is it safe to follow the instructions from the video to install? Or I need to check something else?
Thank you very much everyone!

And I saw this video: How To: Motorola Defy/Defy+ Jelly Bean (4.1.1) Installation Guide - YouTube
I am wondering if it is safe to move from GB to JB? And if it is possible to go back if for some reason it is not stable? By the way, the version mentioned on the video of JB is the stock version, or custom version? Because if I am correct; the stock versions are not downgradeable, but custom ROMs are downgradeable. Is that all right?
If yes, is it safe to follow the instructions from the video to install? Or I need to check something else?
Thank you very much everyone!