macOS Catalina (10.15) will bring some major changes. Before upgrading, below are some of the main requirements, which may help keep you from facing major problems.

32-bit Application Support Discontinued

Here are several ways to check for 32-bit applications on your computer:

A 3rd party app provides a comprehensive report of 64-bit compatibility:
1. https://www.stclairsoft.com/Go64/.
System Profiler to check on a specific application:
1. Click on Apple Menu > About This Mac > System Report.
2. Go down to Software section and click on Applications.
3. Select the application to check.
4. Look for "Yes" or "No" in the "64-Bit (Intel)" field.
5. NOTE: It's possible for System Profiler to report the application is a 64-bit application, but still not work in Catalina.
A terminal command to check if you are using 32-bit applications:
```
system_profiler SPApplicationsDataType | grep -B 6 -A 2 "(Intel): No" > ~/Desktop/32BitAppList.txt
```
NOTE: The resulting text file will only return applications specifically listed as 32-bit in System Profiler. There could still be 64-bit applications that still do not work in Catalina.

A couple helpful articles describing the problem and more info on figuring out if you are using 32-bit applications:

Crashplan Backup Application Version 6.x Not Supported

Per Atlassian Support, please wait for version 7.x release before upgrading to Catalina.

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