At the end of November 2019, the Japanese Rockman Unity Twitter account revealed that four Mega Man games would be leaving the PlayStation Store. Mega Man 8, Mega Man X4, Mega Man X5, and The Misadventures of Tron Bonne were all revealed to be going away on December 13, 2019. However, after consulting with a Capcom representative, Siliconera has confirmed that this announcement only applies to Japan.
This means that the Mega Man 8, Mega Man X4, Mega Man X5, and The Misadventures of Tron Bonne PSOne Classics will still be available via the PlayStation Store in North America and Europe after December 13, 2019. All four games are playable on the PlayStation 3, PlayStation Portable, and PlayStation Vita.
In the meantime, people with Japanese accounts who want those versions of the game should pick them up before their delisting on December 13, 2019.
Mega Man 8 first appeared on the PlayStation in 1996, and it eventually also appeared on the Sega Saturn and PC. Mega Man X4 originally showed up on the PlayStation and Sega Saturn in 1997, before getting PC and mobile ports. Mega Man X5 first launched on the PlayStation in 2000, though it also eventually headed to PCs. The Misadventures of Tron Bonne was a PlayStation exclusive that first launched in 1999.