In February, OS 2.53 was released by Texas Instruments for the TI-84+. This is unquestionably the best set of upgrades ever issued for the calculator. If you’re a longtime 84 plus user, you’ll feel like you’ve been given a new calculator for free. This video illustrates the improvements and guides you through the upgrade. More recently, a less major update, OS 2.55 was issued, but everything in this video still applies.
The update installs a whole new set of menus on your 84. Fractions now look like fractions, without having to open an app. You also have the ability to work with summations, calculus templates, matrices, and logs of different bases just as they appear in a textbook. Another less obvious but hugely helpful upgrade is the ability to use the arrow keys to travel up and down the stack of previous calculations. This feature is long overdue, but better late than never.