Upgrade from PHPMaker 8

[arbei]

You can open v8 project by v2020 directly, but yes, you need to read the follows first:

• https://phpmaker.dev/doc/migrate2019.htm
• https://phpmaker.dev/doc/migrate2020.htm
  Also: https://discourse.hkvstore.com/t/migrating-to-v2022/655/1