I can't see this in your post, but have you tried contacting Rohit through the community to let him know that there is an issue?

You can leave a comment on the plugin version you're using or you can send a message to him from his profile.

https://elgg.org/plugins/3129473

If you import your external SDK with Composer the autoload file of Composer will automatically be included during plugin boot.

If you (for some reason) aren't using Composer you can simply include your

require_once('shopi-php-sdk-master/autoload.php');

in the elgg-plugin.php

The plugin you mentioned isn't on the community. Anyway, it's already outdated.

You can use other plugins to get what you want. It won't be exactly like Tosh, but you've no other way.

Look at Embed Extender.

This plugin allows you to insert existing objects on the site.

With the bundled plugins Embed and File you can embed the external files.

But you can only do this with existing entities ('blog', 'page' etc).

You need to create a new entity (object) (e.g. 'presentation') to do what you want.

You may need the developer's help to create a custom plugin.

If you don't want to hire a developer, or you don't have enough knowledges, you can use in addition the bundled plugins Blogs or Pages, or Static, Pages Tools.

This is a bug which was introduced in Elgg 4.3

Before it always showed a message like 'your account isn't validated yet'

We'll fix it

follow up in https://github.com/Elgg/Elgg/issues/14162