Evernote people just listed how they support ios4 features in latest update;
Where was I?
iOS4 supports fast app switching, which means that whenever you leave an app, you?ll be able to return to where you left off. Evernote supports this feature, so you can leave the app while creating a note, viewing a note, doing a search, or just about anything else and you?ll come back to the same exact spot.
In the background
The new operating allows applications to continue performing certain tasks even after the user exists the app. In Evernote?s case, the following operations can occur in the background:
?Download note headers: notebooks names, note titles, tags, and other meta data for the note list
?Sync new notes: the app will upload any new or edited notes that are in your pending queue
To ensure that Evernote does not hog your battery and bandwidth without your knowledge, the application does not perform the Premium offline notebook sync when the application is closed.
Keep talking
Audio note now continue recording even when you leave the application. This is useful if you begin recording and audio note and need to reference something you have in another application. To end the recording, simply tap on the red Evernote bar to quickly return to Evernote.