Where did you read that BEx is no longer supported in 7.40??? That note you're referring to mentions only features like "Constant Selection with Append" and "Formulas before Aggregation" as no longer supported. Nowhere does it says that Bex, or even XXL texts for that matter, are not supported in Bex either.
My client is on 7.40 SP5 and still uses Bex extensively without any issue, so I'm not sure why your answer is shown as the correct one.