I am facing R20 version update issue using merchant services in QuickBooks. Mac OS X
Update QuickBooks for Mac
Note: Create a backup copy of your company file before process the below method.
To uninstall QuickBooks for Mac:
Close QuickBooks & then choose Go and Applications from the Finder menu (search bar) on the upper right corner of your screen. After that click, the QuickBooks icon and drag/move it to the Trash.
To reinstall QuickBooks for Mac with latest version:
Go to QuickBooks product updates & then click on Change, select QuickBooks Mac Desktop and select your QuickBooks version. Now you must click on Download. After that double-click the downloaded .dmg file. Now easily drag the QuickBooks Desktop icon to the Applications folder to install.
Note: To verify the update & confirm the release number press CMD + 1 on your keyboard.
Call at 1 (855) 481-5335 in case you get any issue or unbale to troubleshoot the R20 issue in QuickBooks.