Yes season 4 is the final season.
Jessie is ending because Debbie Ryan is now engaged and in the span of the last 4 episodes they will be getting married as their characters in my opinion I think it is a great way to end the show!
I suspect this is the last season, since Peyton List (Emma) is already a regular on The Tomorrow People (on the WB).
no one really knows it could be that one of the main actors just doesn't want to do it anymore or they ran out of ideas for the show
Yes, there has been rumours it was ending on the first series, and this was confirmed by the cast on twitter. Dani said it has been an amazing 10 years, and Bye Bye Beaker. Jessie (Lily), also confirmed.
Jessie = Ieki
Jessie Starnes goes by Jessie.
Jessie Camacho goes by Jessie.
Jessie Bond goes by Jessie Bond.
Jessie Monteiro goes by Jessie Bear.
Get it from Jessie
Debby Ryan
Jessie J is a Christian.