Will this ever be implemented?

Please implement the roll up of subtasks under parent. I have been waiting for this for 4 years!

We are waiting this from 2012...

This makes sense. Just good UX. And that sells. Every time, all the time. Scrolling:bad. In front of you/easy to find/clean:YES! Great App, tho. On a REALLY good track!

Will not be able to use this app without this feature.

Yesss! It's annoying to have to scroll down through several screens of subtasks to find the item I'm working on. Ability to selectively expand or collapse individual tasks would make the app much faster to use.

The reason I want a way to collapse all projects is so I can drill down to the specific one I want. I have a lot of projects with many sub projects and sub tasks. It is very easy to quickly scroll past what you are looking for when it is burried among a long list of sub projects and sub tasks. Sometimes it becomes easier to do a search for the task instead of trying to find it manually and that should not be.

Collapsing of tree structure, copy and move among different trees is a must have.

I have to endorse this. Rather astonished that such a fine piece of software is missing this rather fundamental facility to handle the tree-based hierarchical structure. Phone real-estate is so precious, and without collapsable and expandable task/sub-task abilities, it is just not possible to use this software for a large number of items in a tree structure. If I may be so bold, this is in fact 'crucial' to being able to use any long list of hierachial items. Any disk drive folder structure has had this ability for ten's of years, and there is other software apps on the market that have far less features, yet remain more useful because of the ability to collapse/expand subtasks in an outline view. So strange that this facility is still not added after the requests here for more than two years... I hope you will have this soon, and then you certainly will have a really nice bit of software. Right now, I cannot use it for large projects, so will have to pass for a while. I'll keep an eye on progress though. Good luck...

Easy outlining capabilities (expand/collapse, promote/demote, hoist, re-order) are ESSENTIAL for managing large numbers of tasks -- they are used to organize the tasks into groups, to zoom in on the ones you're currently interested in, and to hide those that you're not. By far best user interface that I have seen for this in a mobile / online app is Workflowy (http://www.workflowy.com) -- it's beautifully clean, simple and easy to use. You should copy this style of interface.
At the same time you need to give the user control over the visibility of parent tasks, since the child (subtask) may not be meaningful without this. For example, consider the task "Project report for Able Baker Corporation" with the subtask "Complete first draft". If this subtask is made visible, e.g. by prioritizing/starring/filtering, it needs to have the parent task also made visible -- otherwise the user cannot tell which client it relates to.

It would be nice if the expand/collapse function was triggered by a double tap, rather than a swipe. What do you guys think?

A button to hide/unhide subtask in any given list or view would be very helpful to get an overview of the various projects and then see the detail of the task to do.

Collapseable subtasks are important. E.g. Grocery list with the items entered as subtasks. I do not want to see a big list of tasks until i am at the grocery store. When working on my list of tasks i have to scroll by the grocery list all the tim. Very annoying. This is one example of why collapseable sub tasks are important.

There are situations where the subtasks aren't tagged with the same context, etc, so they don't show up in the view (indented or not).

Additionally, a visual indicator (other than the note icon) that indicates there even ARE subtasks. As above, if the view is filtering by context, and if the subtasks have no context, then they aren't displayed. This is undesirable behaviour.

I need subtasks to come up on the to do list when they are due, not when the parent task is due.

And also make it possoble to choose to have the subtasks on top of the task on the list.

It is annoying to have sub-tasks follow parents in ToodleDo when the parent due date is changed, but not in UTD. When I change the parent date in ToodleDo, and update the list, the subs follow. This allows me to move all to a new day as a group. But, when I then go to UTD, they are still showing their date, requiring me to update their date to clear them out of a view.

This is related to idea that a subtask should also be reconfigurable to be a sub-project, or sub-folder.

And, have the option to connect, not connect, or re-connect sub tasks with parents during a Sort.