I'm currently using CS5 with a Worldtools plug-in, are there any major improvements regarding working with Arabic and Hebrew text in the newer versions of Indesign?
With a CC subscription, you can download and install a western-language version AND you can download and install a separate ME version to work natively in right-to-left languages. Just make sure you browse it to a new location to get that second version separately from the first version.
Beside what Michael suggested, you may download an older ME copy of InDesign this way you can have it side by side with your latest InDesign English version. For example, if you have InDesign CC 2017 English, you may download along with it InDesign CC 2105 Middle Easter version and keep them in your application folder whether you have Mac or Windows.