CS以前のPhotoshop、ILLstrator、Premire、ArterEffectsのバージョンアップ方法

例えば，CS5 → CS6 のようなアップグレード版の購入はすでに不可能です。新規購入も同様です。

伝手があれば譲渡という方法で入手できる可能性はありますが，その場合はライセンス違反にならないよう注意してください。

〈アドビ製品ライセンスの譲渡〉
https://helpx.adobe.com/jp/x-productkb/policy-pricing/transfer-product-license.html

Google translate - 

How to upgrade Photoshop, ILLstrator, Premiere, ArterEffects before CS

 As of 8-19-19 downloads for non-Cloud programs are back
Program installers https://www.adobe.com/gr_en/downloads/other-downloads.html
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If you are not able to find your program installer at 'other-downloads' read ALL links below
https://community.adobe.com/t5/Get-Started/CS6-Download/td-p/10519526

OR do this, copied from instructions posted by an Adobe employee
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If individuals wish to apply updates to the Creative Suite applications, then they will need to make sure and revert to the update components that were included with that title. If they have Creative Cloud versions of our update components, then the automatic updates will fail.
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I would recommend anyone who wishes to revert to Creative Suite, or other older Adobe perpetual software title, complete the following steps:
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Uninstall all installed Adobe Applications using the included uninstallers
- https://helpx.adobe.com/creative-cloud/help/uninstall-remove-app.html
Download and run the CC Cleaner tool
- https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html
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Completing these two steps will leave an individual in an excellent position to then install older Adobe applications. When the applications are installed, they will also receive a version appropriate version of the update and licensing components. (added by me... do NOT install any Cloud programs until AFTER your old program updates are done, or you will be right back in the situation of old program updates not working)
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These same steps should also be utilized if someone is canceling their CC membership and wants to revert to Creative Suite. If they do not, then they may receive messages about needing a subscription to use their perpetual software title.
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As for the question of if updates are available through our chat support team, THEY ARE NOT CURRENTLY PROVIDED. The only files that are presently being provided are the original installers that were released for each version. These are the same files that are available within Account Management, if someone purchased from Adobe directly, and choose the download option at the time of purchase.

以上の方法が分かりません。

Adobeに電話したのですが、要領がはっきりしませんでした。

無理なのでしょうか？