On your Minehut server, you cannot change the version that your server runs on, you can, allow older versions to join though. This can be done through downloading plugins such as ProtocolSupport which will allow versions from 1.8.9+ to connect to your server. Protocol may have some bugs which could ruin certain aspects of the game, but it’s still functional.
Additionally, you can also use the 3 Via plugins, ViaVersion is the base of these 3 plugins and is required as a dependency for these plugins. If you also install ViaBackwards, it will allow support from clients that are on 1.9+, ViaRewind will also add support for 1.8 to 1.9.9
However, you may want to have your server use the mechanics of 1.8 PVP, this is also possible! If you’re trying to implement 1.8 PVP, then you can install either OldCombatMechanics or Combat Elite which create the 1.8 combat that you’re looking for.