Last week I had a batch job running with FuelSDK-PHP v0.9 against my Client's SalesForce / ExactTarget email marketing account to download subscribers for analysis in another system.
After downloading some 2.1M subscribers (in batches of 2,500 using the moreResults=>1 response node) their API suddenly just returns a 302 Object Moved, and their PHP Classes spit out "Version Mismatch".
Nothing in my code has changed, and yet even when I create a new hub app to get a new client ID and Secret key, it still just issues a 302 to my Subscriber Retrieve query. It's also way, way below the 50,000 API calls per day courtesy limit. In fact, I am now getting this same 302 redirect response on Monday morning the first time I run the script after the weekend.
If anyone is interested I've posted my entire code here - It's far from being complicated; based on their examples. I also posted about it in the SalesForce Developer Forums.