Finally 0.9.28 stable version is ready with a massive channels update onboard:

— Now the channel creator can edit any post while each channel admin can edit their own posts. Also any member of a supergroup can edit their messages to this supergroup.

— The channel creator can switch on the signatures in the channel edit box and after that all posts will be followed by the authors name.

— Each channel admin can send «silent» posts which won't produce any notifications for the subscribers.

— Any post in a public channel now has a direct URL. You can get it from the context menu of the post. For example, this post has such link: https://telegram.me/desktop/26