MOJANG WHAT WHY DOES IT SAY BELOW 1.21

I was going to load webdisplays with the mcef mod but I left my worldedit mod in the mods folder i launched forge 1.19.2 to see the mod worldedit 7.2.15 was in there, But It said 1.20 or above, below 1.21, 1.21 is not out yet what is that supposed to mean?, Because I am pretty sure the next update is going to be 1.20.2, But Not sure about that 1.20.2 could be, So what this mean below 1.21. (What I put in affects versions is not right because i cant find with WorldEdit 7.2.15 Mod for 1.20.1 on 1.19.2, So I put Future Update)