[2020] Elo System Question

Originally posted by Akeno: Say I peak plat 1 but then drop to plat 3 as the season ends. Will my Elo next season be based off my highest rank that season, the Elo I ended on or will it be a clean slate?

You'll start the next season at or around the MMR you left off at in the previous season. That's to prevent a Diamond or someone who's accustomed to high elo lobbies playing against a Copper or those used to low elo lobbies.