what is the compatible version of High Sierra?

[Bitsaegim]

I'm going to install Photoshop and Lightroom on an old Mac.

The Mac version is High Sierra. the creative cloud app is installed, but other programs can not be installed. I wonder if it is compatible until the 2019 version.

[John T Smith]

Adobe now offers the current and ONE older version via the online program manager
.
I do not know how far back this process will go, but try this link
-NOTE that you will have to search the site for your specific download
Direct Download Links https://prodesigntools.com/tag/ddl MAY help
-you MUST do what it says in Note: Very Important Instructions
-https://prodesigntools.com/adobe-cc-2015-direct-download-links.html#download-instructions
-the prodesign links go directly to Adobe's file server, so this process will
--only work until Adobe completely removes the old version(s) from the server
.
IF/When you do have a download, be sure to copy it to AT LEAST one external device
-since Adobe does sometimes remove old versions from the server
-a usb flash drive or external hard drive, or write to a DVD

[ProDesignTools]

As John points out, the most recent versions of Creative Cloud (2022 and 2021) do not support macOS v10.13 "High Sierra"...

The last version which fully supported it was the 2020 release. 2019 of course will also work fine. The link John posted above can help you get older versions of the software which will run on High Sierra.