IMHO, you should only use the updates that Tmo has posted on their web site. I know a lot of people talk about releases of newer updates before Tmo gets them. You can find them at the very top of this section of the forum.
It is true that the other OS downloads are essentially the same, I play it safe.
To find them on Tmo, go to MY TMOBILE at Unsupported Browser
. There will be a link in there that says "Upgrade my device". Click that and a window will open with the current OS and download manager software for your Pearl.
You can watch this forum for notices when Tmo posts new software to their site.