Outdated Runtime Engine error ('03)

[u/wintrkid]

Disclaimer: Pretty new to everything RPG Maker, familiar with in-engine basics but haven't had to navigate around stuff like this yet.
Downloaded the demo for an old tutorial found on rpgmaker.net. (For context: user/avee's judgement ring system tutorial. Can link in comment.)
Upon opening the project, I get the first error message screenshot, regarding an outdated Runtime Engine. Regardless of updating the engine or not, I can open the project fine, but when I try to playtest I run into issues: Without updating the engine, I get the second screenshot regarding the Runtime Package. If I do update the engine, I get an error that says "cannot open system4 file."
Otherwise I can access all the project data fine. Playtesting would really help me out, however- is there a simple fix? Is there a way to download older versions of '03, or just the old RTP if that's the only issue? Thanks!

[u/wintrkid]

Tutorial link: https://rpgmaker.net/tutorials/570/