Unfortunately, there is no choice but to find a way to work properly if the connection is broken. Blizzard does not yet have a release date for the update. The company just announced an early notice. If you are waiting for a patch, you may suddenly need to reinstall the entire game. Once the game giant announces the date and time, you can schedule another download as you planned later.
Company announcement contents are as follows.
"We wanted to let you know ahead of time what we could expect from our next big patch. We do not currently have this release date / time, but we will update this thread once.
The next major patch will have a fundamental change to the game client. The number of backend changes we are putting in is large enough to effectively patch the current content. As a result, when the next patch comes out, the client is completely reinstalled to handle these changes. This is not an ideal function for people on a metered connection, so this presentation will help you prepare for future updates.
Thank you for your patience, and see you all in the game! "