How to update an Amasty extension?
Below you can find a step-by-step guide for updating your Amasty extensions to latest versions.
Before updating the module, it's recommended to create a backup of the modified extension files (if any). When the update is finished, you can re-apply the custom patches and/or re-upload the altered files from the previously created backup if needed. 
Please note that manual module update and installation have been deprecated in the amasty.com platform, and all Amasty extensions are available for installation only via composer. Thus, if module update is required and it was previously installed by manual upload, the package needs to be removed from app/code/Amasty and installed via composer instead.
Step 1. Ensure that you're using project-level composer keys from License Registration tab in your amasty.com account, as old account-level composer keys from Products tab have been deprecated and disabled. These old account-level keys don't grant access to module download anymore. For accessing extensions, project-level keys need to be utilized.
Our developers have come up with an easy an quick migration process for old keys that takes only a couple of clicks in your account and doesn't require changing anything in your Magento installations. Please, follow this guide to migrate your keys: How to switch to project-level composer keys from old account-level keys? If you already have a project, you can find project-level composer keys using the following article: Where can I find Composer access keys?
Step 2. Log in to the server via a command line and proceed to the root Magento folder.
Step 3. Execute the following command:
composer update amasty/<composer_module_name>Here <composer_module_name> is the Composer name of the extension you are updating. To find the Composer name of the module, open the Products tab of your account and scroll down to the Composer packages section:
It is also possible to update multiple extensions with one command:
composer update amasty/<module_name_a> amasty/<module_name_b> amasty/<module_name_c>
Or update all installed Amasty extensions at once:
composer update amasty/*
Step 4. After the extension update, the following commands should be run:
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy (your locale)