Luckily now essentials has got their dev builds easily downloadable, whereas before you had to be like a registered beta tester and suchlike which was a lot of effort considering everyone else manages to get their dev builds out with no issues.
Annoyingly their site doesnt just let you use "wget" (for those who don't know - a command line linux utililty to get a file from a website) on their download, cos it bounces you to some stupid login page, so what you have to do is download it locally, and then FTP it up. Right pain in the backside when everyone else it just works
Let me know if theres any issues that creep up. It is still running a dev build, so there may be some issues still, but it should at least let you connect from 1.2.4!