Below are step by step process to upgrade Cumulative Updates(CU) in SQL Server 2019 on Linux.

Run below query to check current SQL Server version.

SELECT SERVERPROPERTY('productversion') 'ProductVersion', SERVERPROPERTY ('productlevel') 'ProductLevel', SERVERPROPERTY ('edition') 'Edition'

SQL Server version/CU can be verified using OS level command as well. Follow this link to check SQL Server 2019 build version and its corresponding CU.

sudo yum info mssql-server

From above output, it is clear that SQL server 2019 is currently running on CU12 and currently available upgrade package is of CU17 and we would upgrade it to CU17. Below is the command to upgrade SQL Server CU.

sudo yum update mssql-server

We can see that upgrade is completed now and we will verify Installed version by running below command. We will also verify by logging into SQL Server.

sudo yum info mssql-server

Below query can be used to check installed and available packages

sudo yum list mssql-server –showduplicates