Gravity Forms PayPal Payments Standard Add-On v1.10 is now available via automatic update and the Add-On downloads page. This is a maintenance release that includes recommended changes by PayPal as well as a new hook for developers to easier interact with PayPal's IPN.
Why v1.10 and not v2.0? We are holding off on incrementing all Add-On updates to v2.0+ until they have been fully converted over to using the Gravity Forms Add-On Framework. This change will be coming soon to the PayPal Payments Standard Add-On. However, don't let that stop you from updating now. We always recommend users update WordPress and plugins when updates are available.