If there is a new version available for your AbanteCart, you will have a notification in your message box of AbanteCart administration.
You should upgrade version to version. Upgrades are available only from the prior version to next. Make sure version is not skipped.
Start with updating AbanteCart with the lowest upgrade package number. After you update, start update with the next sequence number.
Recommended that you DO NOT upgrade AbanteCart on live site. Depending on your server or OS configuration upgrades might not go all the way through and you will need more time for the manual upgrade. We suggest you upgrade your test site first and always create backups. If you do not upgrade for a long time, you will need to run all upgrades in between. If you are made Core modifications in any of the files that changed, they may need to be redone.