It seems that !chain, which shows you a Jerry Seinfel chain, doesn't work anymore.
could you please clarify what feature are you referring to and what issue are you experiencing with it?
When you added the string "!chain" to the text of a recurring task, you could see, next to your task, a serie of white squares.
One square would become green each time you accomplished the recurring task.
This feature seemsto have disapeared.
unfortunately, this feature has been indeed deprecated and is no longer supported. One of the reasons why we've removed is was an issue with supporting it on mobile devices.
That's a real pity. Why can't it be continued, only with limited or no functionality on mobile platforms?
It's one of the features I use the most.
we're sorry for the inconvenience. You're welcome to add a feature request to our Votebox: http://todoist.com/Vote/