How to Make Your Server Compatible with Older Minecraft Server Versions
The green checkmarks are what versions your server allows
1) Login to your Panel Account at https://panel.humbleservers.com and click your server's name
2) Stop your server
3) Make sure your server is a spigot or bukkit server!
3) Startup your server (so the plugin folder gets generated), once the plugin folder is generated or you already have a plugins folder, stop your server.
4) Click on your plugins folder
4) Download a bund click the top right uploadtton on the panel and select the plugin called ViaVersion( https://www.spigotmc.org/resources/viaversion.19254/ )
5) Once the uploading bar is fully green, start up your server