If you need to update Magento 2 Google Tag Manager by Magefan, please follow the steps below.

Note: the update instructions depend on the method the Google Tag Manager extension was installed with.

Update using composer

If the Google Tag Manager module was installed via the composer (check if vendor/magefan/module-google-tag-manager folder exists), then you need to run these simple CLI commands in Magento 2 directory:

composer remove magefan/module-NAME
composer require magefan/module-NAME ^x.x.x
# replace NAME with:
# google-tag-manager - for Basic plan
# google-tag-manager-plus - for Plus plan
# google-tag-manager-extra - for Extra plan
# replace x.x.x with the version you want to use
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy

If you want to upgrade to the Plus or Extra, check this guide on how to upgrade Google Tag Manager plan.

Update using archive and FTP

If the Google Tag Manager module was installed via FTP (check if app/code/Magefan/GoogleTagManager folder exists), then follow these commands:

1. Download the latest version of the Google Tag Manager extension archive from magefan.com.

2. Extract archive.

3. Make the backup copy of the app/code/Magefan/GoogleTagManager, or app/code/Magefan/GoogleTagManagerPlus, or app/code/Magefan/GoogleTagManagerExtra folder on your server and then remove it.

4. Using FTP, copy app folder from the archive to your Magento 2 Directory. 

Update Magento 2 extension via FTP

5. Run update CLI commands in Magento 2 directory:

php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy

Note: if you don't want your website to be down during deployment, try these zero downtime deployment commands for Magento 2.