Plugin not running on MacOS

[mxdanger]

Currently, my idea of the problem is quite vague. I've tried multiple related JOSM (.jnlp) around the required version of JOSM required for this plugin. I'm using MacOS High Sierra 10.13.1 with Java 8 update 151. I highly suspect that Java 8 is the culprit of the problem but I have no way to test it as I can't find a way to download Java 7. The requirement for the latest update of the plugin is JOSM 13174 and when I run 13174 or higher it prompts that it can't load the plugin. When I'm using a version lower than 13174, for example, 13170 it prompts that I should use version 13174. I'm quite sure this is an Issue, although I could be doing something incorrectly.

Here is my vaguely related question.

[kendzi]

It is known problem with plugin using webstart (jnlp) and java 8. Unfortunately currently the only way to run it is to download standalone version of JOSM from:
https://josm.openstreetmap.de/josm-tested.jar

[mxdanger]

That file did not work because it's version 13170.

I ran the snapshot version 13174 of JOSM jar and it works.

It seems like it inconveniently works with just jar and not webstart.