The year is already shown, if the post isn’t from the current year. For example, a post from May 2019 will show as “May '19” where the apostrophe before the “19” indicates it’s the year, not the day. A post from May 19th of this year would look similar: “May 19”.
So:
May '19 = Post was made in May of 2019.
May 19 = Post was made May 19th of this year.
Here are some old topics to look through to see this in action:
https://forums.plex.tv/search?expanded=true&q=before%3A2020-01-01%20order%3Alatest_topic
