I use a custom backend uri path for my OctoberCMS installations, and this plugin doesn't work because of that.

Looks like the plugin uses a hard-coded /backend path. I would suggest pulling this value from the cms.php config file.

Here's what I updated to make it work: routes.php

$backendUri = trim(config('cms.backendUri', 'backend'), '/');

Route::get($backendUri.'/revisions/{id}/{model}', "SaurabhDhariwal\Revisionhistory\Controllers\RevisionHistory@revisionDetails")->name('revisions.history');

SaurabhDhariwal\Revisionhistory\Controllers\RevisionHistory:

public function revisionDetails($id,$modelName){
        $backendUri = trim(config('cms.backendUri', 'backend'), '/');

        return Redirect::to('/'.$backendUri.'/saurabhdhariwal/revisionhistory/revisionhistory/revisions/?id='.$id.'&modelName='.$modelName);
    }