Is there a program GTD and at the same time to control the timing?

Question

Time Management

I would like a program for GTD, (it is desirable to have a version for android and for a browser)
, but, in addition to the tag system, so that it would be possible to create tasks with stages in it (for example, subtask No. 2 can start running only after subtask No. 1 is completed) ,
as well as to have a calendar function and track deadlines until the deadline...
(there is a rather sophisticated system toodledo.com, but there are some problems with versions for android and with calendar functions, subtasks)

Answer 1

Todoist is the most suitable, after MLO. I went through GTD for 3 years, the day before yesterday I finally moved to tuduist.
From the TOR - there is no correspondence only to this paragraph:
"(for example, subtask No. 2 can only start to be executed after the completion of subtask No. 1"