If you need to update Magento 2 Size Chart Extension by Magefan, please follow the steps below.

Note: the updating instructions depend on the method the Size Chart extension was installed with.

Update using composer 

If the Size Chart module was installed via the composer (check if vendor/magefan/module-size-chart folder exists), then you need to run these simple CLI commands in Magento 2 directory:

composer remove magefan/module-size-chart
composer require magefan/module-size-chart ^x.x.x
# 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

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

Update using archive and FTP 

If the Size Chart module was installed via FTP (check if app/code/Magefan/SizeChart folder exists), then follow these commands:

1. Download the latest version of the Size Chart extension archive from magefan.com.

2. Extract the archive.

3. Make a backup copy of the app/code/Magefan/SizeChart folder on your server and then remove it.

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

Update Magento 2 extension via FTP

4. Run update CLI commands in the Magento 2 directory:

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