Sony has recently updated that the new update is going to add a major change in PlayStation Plus service that will exclude PS3 and PS Vita titles. This means only PS4 titles will be the part of PlayStation Plus service. So just in case if you still have the old console or the portable platform with you, you cannot benefit anything from the service once the update is rolled.
PlayStation Plus service allows members to enjoy discounts, exclusive titles, online multiplayer and lot of features with monthly savings. After the update is rolled there won’t be old titles to be the part of services. Below is the official statement:
This will not affect games you have already downloaded or downloaded before March 8, 2019. These games will still be part of your PS Plus game library as long as you subscribe. Your backups and other PS Plus benefits will remain unchanged. The only change is that PS Plus games will no longer include new PS3 and PS Vita games after March 8, 2019.
According to Sony a lot of fans go for PS4 titles only and the number has been growing with time. Prioritizing the benefit for PS4 users on the subscription service will let the fans enjoy more new content every month along with exclusive discount and network services.