I have tried kdenlive 16.07.70 and 16.04.1 and in both versions the speed effect is missing and I really needed it for a project today. Has it been removed or is there a problem here that needs to get solved?

Cheers

Also just tried 16.04.0-2 which was also broken, and finally I found that 15.12.3 was the last version with the speed effect visible

Which distro or package repo are you using? As the speed effect has been switched to a better effect implementation that now also supports audio, but only available in recent MLT, which MLT version do you have installed?

The speed effect works with 16.04.0 with proper MLT installed, used here in a project but then ditched as I work with H.264 footage so I usually simply reencode the frame time positions to get a reliable speed effect.

Yeah, everyone needs it in her project today.