Just go to your nopCommerce admin area and check "Current shopping carts" section. Are you excited? Want all the items to be converted into sales? Abandoned Cart Recovery plugin will help you with it!
Customers often abandon their carts for a various of reasons: complicated checkout process, website timed out, not enough time to complete a checkout etc. Abandoned Cart Recovery tool can send e-mail reminders about it. Just configure the interval and some other settings and you are ready to return customers!
There is a free demo version available with only one restriction - up to 10 messages can be sent.
For documentation and details please refer to this link. You may also find a plugin for your older nopCommerce version there!