Important disclaimer: Starting with ShortPoint version 7.1.5.xx (New Upgrade), you can no longer create multiple site collection app catalogs and install different ShortPoint versions into them. You still can upload the ShortPoint app to the site collection app catalog to control who can add and install ShortPoint in specific site collections. 
For more information, check these solution articles:
● ShortPoint SPFx New Upgrade for Office 365 and SharePoint 2019
● How to Control Who Can Add ShortPoint SPFx App to the Site
● I cannot test the new release on the site collection that uses Site Collection App Catalog? What for can I use it then? 

Before we begin

This article is for Office 365 SharePoint Environment. Also, make sure you have completed the following steps before you proceed with this article:

• Prerequisites 1: Set Up Site Collection App Catalog (5 minutes)
• Prerequisites 2: Enable Scripting Capabilities  Recommended
• Download Latest version of ShortPoint SPFx

Step 1: Open Site Collection App Catalog

We assume that you already know the site collection you have configured the App Catalog on. 

Open the site where you have set up the site collection app catalog on.
Click on the cog wheel in the Suite Bar and choose Site Contents from the drop-down:

Then open Apps for SharePoint

In Classic View:

In Modern View:

Step 2: Download latest version of ShortPoint SPFx

1. Download the latest version of ShortPoint SPFx
2. Extract the file ShortPoint-SPFx_XXXX.zip
3. You will find after extracting the file: shortpoint-spfx.sppkg
4. Upload shortpoint-spfx.sppkg as described in the following step: 

Step 3: Upload ShortPoint SPFx to App Catalog

In the pop-up, click Choose Files:

Click OK in the pop-up window:

From your computer, choose the shortpoint-spfx.sppkg file. Press Open:

Press OK:

I can not add the new package to App Catalog!
If the step is not completed successfully and you have encountered a problem adding the package to the App Catalog, please click here to fix the issue.
OR
If you get error saying Cannot enable the site collection app catalog feature in this site collection because it has not been approved by the tenant admin, check our resolution article for this issue.

After the upload is completed successfully, you will be prompted to deploy the solution. 

Press Deploy. This will enable ShortPoint to download the latest files from our global CDN d2zzvnmppezkx.cloudfront.net:

OR

Make sure you are in classic view:

Select ShortPoint SPFx App: 

From ribbon, click on Deploy:

Press Deploy. This will enable ShortPoint to download the latest files from our global CDN d2zzvnmppezkx.cloudfront.net:

After this step is completed, you will see a message on the top highlighted with green, indicated that the upload is completed successfully.

Important: You should see that ShortPoint SPFx is Deployed

If you get the following error that the App was not Deployed:

Then all you have to do is to click on the app and try to Deploy again:

To get more help about above deployment error, check out our article.

NEXT: Add ShortPoint SPFx to SharePoint Site (1 - 5 minutes)