Flex support has been removed in 2017. This was announced years ago and actually occurred later than Adobe originally planned.
Thank you @bob_baldwin,
So there is no way I can use the extension as was done in CC2015?
To migrate the code, you know if there is a quick way to migrate? Does using HTML5 and the current code?
Thank you very much!
Correct, Flex has been removed. You either need to create native C++ extensions or use HTML5 extension panels. There is no quick way to migrate, but you can look here: Apache FlexJS 0.6.0 and Apache Flex FalconJX 0.6.0 Released : Apache Flex to see whether these tools will help in your migration process.
Thank you Bob Baldwin for the answer.
Just want to be sure : You are saying that it is not possible to manually copy the content of an extension (the SWF with all the assets) for CC 2017 like it was for CC 2015 ? (by putting the files in C:\Program Files (x86)\Common Files\Adobe\CEP\extensions folder) ?