I have lot old cp fles. pls let me know how we can open and pulish old cp files sonce old cp files are not supported Flash with windows 10 browsers.
Thanks & Regards,
You simple will not be able to open them in CP2019 for many reasons:
It is just a waste of time. Recreate those projects. If they don't have lot of interactivity and you find an old browser to play the output, you could capture them with Video Demo while playing. Output will be passive video (MP4) but you can use Captivate to convert to interactive video, adding Knowledge check and Content overlay slides.
I doubt that you'll be able to use the library as external library for the assets, as is possible for projects created from CP5 on.
Have a look at this post:
Agree with all of the above - way to much work to update - better to recreate - if you open in Cap 6 then you could save as cptx. and then open the external library in 2019. It would allow you to grab the Library Assets to begin recreating the slides.