That's right, 4.29 is the chapter 5 update, with two new quests, a ton of bugfixes, NC+ support for SX-399 in the mines, new costumes, and more! This will be gated for people who spent at least 1 dollar on the game for one month, then it becomes free for everyone.

New Stuff:
New Secrebot quest (starts after the LRT facility)
Runestone upgrade quest (starts after the LRT facility)
SX-399 can help in the mines (NC+ only, must complete Sprocket City first)
Use electrosprite form to power jump the gamma labs door and skip the data core! Yay!
New trainer, spend money to get exp!
New fortune teller, who will show you map pins to help find catalysts!
Code modernization, bugfixes, and hopefully lots of fixed memory issues.
Voice acting for the chapter 5 characters