I think the big question would be, why would you consider upgrading your CMS and still use an unmaintained framework for your web application?

DD4T 2.0 is the current and maintained release, there is full support in there for using the Web 8 CIL (https://github.com/dd4t/DD4T.Providers.SDLWeb8.CIL), you should be able to use DD4T 1.31 with the Web 8 in process API, and even the CIL, since they are backwards compatible. You can simply do that by updating the assembly bindings in your `web.config` like I described in my article about using [DXA 1.2 with Web 8][1] (please note DXA is using the DD4T provider, hence the similarities, although you might need to do some additional steps for DD4T specificly). 


  [1]: https://community.sdl.com/products-solutions/solutions/customer_experience_cloud/digital-experience/tridion/tridion-developer/b/weblog/archive/2015/12/23/dxa-1-2-and-web-8