Regardless of DB terms and conditions, which are fiendishly complicated, you are in any case entitled to [EU rail passenger rights](https://europa.eu/youreurope/citizens/travel/passenger-rights/rail/index_en.htm#cancelled):

>  If you are delayed due to a cancelled train, meaning you would arrive at your final destination with a delay of more than 60 minutes, you have the right to choose between:

> * a refund of your ticket within 30 days – this may be a full or partial refund (covering the part of the journey not made), and a return journey to your initial point of departure, if, the delay due to the cancelled train prevents you from fulfilling the purpose of your trip, or
> * **continuing or re-routing your journey under comparable conditions to reach your final destination at the earliest opportunity**, at no additional cost, or
> * continuing or re-routing your journey at a later date of your choosing under comparable conditions, at no additional cost. This includes alternative transport to get you to your final destination when the train is blocked and the service is suspended.

(emphasis mine)

Some travel companies may send you a new ticket for a different train, but in the case of DB, they will notify you via e-mail and/or the DB Navigator app telling you that your *Zugbindung* is cancelled, and you can figure it out yourself.  Clearly, travelling an hour earlier should count as a *journey under comparable conditions*, so this will certainly be allowed.  

It could be a bit more muddy if you need two trains, your first train runs, but your second train is cancelled, and you want to take an earlier initial train to catch an earlier second train.  Within Germany this should work, but when I tried that with a journey starting in Switzerland (and the German connection being cancelled), I was told I couldn't do that (which I doubt is correct, but I'm not sure if EU passenger rights apply in Switzerland). 

In case of doubt, you can always ask the *Zugbegleiter\*in* (train supervisor).  They have substantial freedom to authorise your travel or not.  They can and often will let you travel even in cases where it normally wouldn't be allowed.