In brief: If you've been an avid user of Apple's iBooks Author or iTunes U apps, the company has some sad news for you: starting on July 1, the former will be discontinued for new users the latter headed for the chopping block in late 2021.
If you haven't heard of either of these apps, we'll break them down briefly here. iBooks Author is a free Apple-exclusive tool that lets macOS and iOS users easily create their own e-books with a simple drag-and-drop interface.
You can select backgrounds, add animations and photo galleries, change fonts, adjust page layouts, and much more. iTunes U, on the other hand, was a much more ambitious package. In addition to housing a large catalog of free books, lectures, videos, and other educational materials from top universities and colleges, it acts as a class management tool for teachers and students.
Instructors can use iTunes U to grade student work and create lesson plans, whereas students can use it to view their assignments, submit finished work, and ask 1-on-1 questions.
Apple's decision to put these aging apps out to pasture does make some amount of sense. Two newer apps, Classroom and Schoolwork, have both effectively replaced most of the functionality of iTunes U (though neither app has the free learning material), and Apple's Pages tool has a similar featureset to iBooks Author.
Still, if you're not too keen on swapping over to these newer apps yet, you aren't entirely out of luck. iBooks Author won't be available to new users come July 1, but it won't delete itself from your devices. You can still use it to your heart's content past that date, you just won't receive any further updates. Additionally, if you do decide to make the switch to Pages, Apple is planning a "book import" feature to help you transfer your work over.
As for iTunes U, Apple hasn't announced any plans for its post-discontinuation usability, but its end-of-life date is still about a year and a half away, so there's no need to worry about its shutdown at the moment.