Every server reports which Minecraft versions it accepts. Many Java servers use ViaVersion, so you can join with an older or newer game version too. A server is listed under every version it supports.
26.xVersions of 202667 Server · 66 online1.21Tricky Trials2024 · 68 Server · 67 online1.20Trails & Tales2023 · 65 Server · 64 online1.19The Wild Update2022 · 61 Server · 60 online1.18Caves & Cliffs Part II2021 · 61 Server · 60 online1.17Caves & Cliffs Part I2021 · 61 Server · 60 online1.16Nether Update2020 · 62 Server · 61 online1.15Buzzy Bees2019 · 61 Server · 60 online1.14Village & Pillage2019 · 61 Server · 60 online1.13Update Aquatic2018 · 61 Server · 60 online1.12World of Color2017 · 61 Server · 60 online1.11Exploration Update2016 · 61 Server · 60 online1.10Frostburn Update2016 · 61 Server · 60 online1.9Combat Update2016 · 61 Server · 60 online1.8Bountiful Update2014 · 60 Server · 59 online1.7The Update that Changed the World2013 · 48 Server · 47 online
Bedrock Edition
Bedrock Edition (phone, console, Windows) always runs the current release, so the versions above apply to Java Edition.
Which version to choose
Play the newest version if you can, most servers accept it. PvP players still choose 1.8.9 for the old combat without attack cooldown, and modded servers often run 1.7.10, 1.12.2 or 1.20.1.