Francesc,
First of all, congratulations for MyEclipse 5.5 M2! Impressive!
Thank you very much. I must admit, this one hurt a bit. 😉
That’s very peculiar indeed. Updates won’t be offered from any of the GA releases (like 5.1.1) but should show up for an M1 install since the update is only a minor service level. If you try it again this morning and it still doesn’t show up for you, I’d suggest that the fastest way to get a working install is simply to download our full-stack installer and install it to another location. Once installed, just open your existing workspace with the new version. You can then uninstall M1 when convenient, or leave it installed as a “backup” for a little while.
This is likely faster than using the update manager anyway since the updates are so massive the number of downloaded files is very large. Downloading the single full-stack installer is generally faster than a ton of much smaller files anyway.