How to distinguish an IPB 2 and IPB 3 forum?

[Prazsky]

Trying to make forum templates but having a hard time distinguishing between IPB 2 and IPB 3 forums as this information is not always found in the html source.

Can anyone help?

Thanks.

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Added after 3 Hours 20 minutes:

So nobody knows anything?

 

[Amfidiusz]

Give us examples of such forums. IPB3 has eg. reCaptcha used in its registration form, is more Ajax loaded and has a sidebar. IPB2 on the other hand has got a My Assistant tab and a lo-fi version.