Frank Marshall, producer of the Bourne trilogy, updated his Twitter profile with the following messages:

Bourne4 is in the works for Summer 2011…

George Nolfi is the writer of Bourne4, should have a draft by June.

If they keep on target this would mean Bourne 4 should start filming sometime next year. Matt Damon and director Paul Greengrass have already signed up to return, and George Nolfi wrote The Bourne Ultimatum so we can expect a film as good as the previous ones.

With producers, directors and actors revealing information on Twitter we can expect more of these mini updates.