Update SharePoint 2013 workflow without stopping running instances (VisualStudio 2012)?

Hi,

I'm developing a complex SharePoint 2013 workflow in VisualStudio2012 and I want to ensure running instances of the workflow continues even if I update the same workflow with bug fixes.

How can I achieve this in SharePoint 2013 On premise and Online?

I've come across these pages:

http://blogs.msdn.com/b/yardman/archive/2010/04/14/versioning-a-visual-studio-sharepoint-workflow.aspx

http://social.msdn.microsoft.com/Forums/en-US/f776aef2-1ba4-47af-b3aa-3ff23e1ed274/upgrading-new-versions-of-workflow-with-running-instances-

but they seem to be for 2010 versions. The tags don't match and a lot of things are different.

Have anyone done this (yet) in 2013 version?

HENCE! The workflow must be able to migrate to SharePoint Online! 

The expected scenario is that the workflow is running in 5 on premise instances and 2 online tenants with about 150 constantly running workflows instances on each installation. Therefore we have to find a way to safely update the workflows without breaking ongoing processes. 

Greetings,

Sören