PlayStation is currently sending out emails to remind users about upcoming changes to the PlayStation Plus free games program

Per the email:

As a reminder, after March 8, 2019, the Monthly Games provided to PlayStation Plus members will no longer include PlayStation®3 (PS3™) or PlayStation®Vita (PS Vita) titles. Any PS3 or PS Vita Monthly Games downloaded or previously added to your Download List prior to March 8, 2019, will still remain playable for as long as you remain a PlayStation Plus member. Beyond March 8, 2019, PlayStation Plus Monthly Games will only include PlayStation®4 (PS4™) titles. All other features and benefits of the PlayStation Plus service will remain unaffected.

Further actions
If you do not wish for your PlayStation Plus membership to continue after this change has taken place, cancel your subscription or turn off auto renewal so that your membership period ends by March 8, 2019. When you cancel your membership, your subscription will end at the conclusion of your current billing cycle and you will not be charged additionally. You can use these direct links to check when your next subscription payment is due and manage your account. You’ll need your Sony Entertainment Network sign-in ID and password to log in to your account:

Check your renewal date
Manage automatic wallet funding
Add or delete a payment method
Cancel automatic renewal