Update: The above tweet has confirmed more or less what we know so far. Unfortunately, the S II is sorely missing from the list.
We have previously reported that the Samsung Galaxy S III will be the company’s first handset to be updated to Android 4.1 Jelly Bean, followed by the Galaxy S II and Galaxy Note. The flagship Galaxy S III will reportedly receive an update by the end of the Q3 with the other two Galaxy devices receiving one in Q4 as Samsung is reportedly close to finishing up the update on the Galaxy S III. While there's no official word on the issue yet, GSMArena has mentioned that an August or September time frame would be realistic.
A leaked video of an official Samsung Jelly Bean 4.1.1 ROM running on a Galaxy S III has since been uploaded to YouTube, further supporting the above allegations. The ten-minute clip show us how the latest OS looks like with TouchWiz. Nothing much has changed in essence but of course, integration of Google's new services, like Google Now and Voice Search for example, can be seen during the video. Smoother navigation is also noted due to Project Butter.