PowerPack can be updated manually very easily on the site when remote updates are not showing up.
Please remember that while updating PowerPack manually close all the open pages on the website so that they do not get affected during the update process.
Step 1: Go to Plugins Manager in WordPress Dashboard and deactivate and delete PowerPack from there.
Step 3: Now, go to WP admin on your site. Click Add New option under the Plugins menu.
Step 4: Click the Upload button and select the bbpowerpack.zip file from your computer.
Step 5: Once the upload is complete, click the Activate button and the version of PowerPack should be active to use.