Summoning Salt did a great video on Tetris a few months ago. Before hypertapping and rolling, the level speed was the limit because people didn't think the pieces could move to the edges fast enough. Once that problem was solved they started to encounter glitched color palettes (on level 146 and 148) with dark colors like blacks and grays, making it difficult to see the pieces.
Then at 155 you can start encountering game glitches, and people started trying to crash the game, as it would represent "beating" it (because the game ended without the player losing). After that was accomplished the community went back to playing on a different version that didn't crash. However, before getting to the "rebirth" level of 255, they had to get through level 235, which instead of 10 lines takes 810 lines to clear due to a glitch.
This video from May ends without anyone getting past level 235, so looks like it took just a few more months to accomplish it. Plus it was done by someone who wasn't mentioned toward the end of the video (though he does come up at 46:30).
The whole video is good but if you're familiar with the movement techniques you can start at the section about colors https://youtu.be/mOJlg8g8_yw?t=4531
Wonder if SS will put out a small addendum at some point soon.