You may click the download link of the version you need and install it on your computers again.
Note:
1. If you click the download link, but the program is not downloaded, you may also try to copy and paste the link to your browser to open it. Or you may go to the PDFelement download center below and scroll down the page to find the version you would like to download: https://pdf.wondershare.com/download.html
2. After reinstalling the old version, please make sure you use the correct license email to log in, so the software can be activated. If you forget the password, you can reset it via this link: https://accounts.wondershare.com/web/reset?account_type.
3. If you still have trouble downloading or activating the old versions, you may contact support. We will get back to you as soon as we can to help you out.