The PSN Store for the PS3 and PSP will shut down on July 02, 2021. The Vita store will close on August 27, 2021. Relevant Armored Core content on the store will no longer be available for download after that point.
AC content currently there:
Armored Core V & Verdict Day DLC
ACVD compatibility pack
PS One Classics (English version: Armored Core 1; Japanese versions: Armored Core 1, Project Phantasma, and Master of Arena)
Edit: Per Sony, the PS3 and Vita stores will remain open because of player feedback. The PSP store, however, will close as planned.