Apple has released iPadOS 17.7.8 for older devices

Apple released a new version of iPadOS for older models, including important security updates
yesterday 05/19. The release is iPadOS 17.7.8, a critical security bug fix release targeted at iPad models that are too old to be able to update to iOS 18. The new release is a follow-up to iPadOS 17.7.7, which was pulled after users reported consistent issues where various App Store apps kept getting logged out.

iPadOS 17.7.8 is available to install for 2017 iPad Pro (10.5-inch and 12.9-inch), and the 2018 iPad (sixth-generation).