Microsoft.Data.SqlClient library follows the latest .NET Core support policy for all releases.
View the .NET Core Support Policy
View GA released version LTS/Current status and support dates here: SqlClient Support Policy on Microsoft Documentation
New stable (GA) releases will be published every six months on a regular cadence beginning with version 1.2, along with 2 to 3 preview releases in between. Long Term Support (LTS) releases will be chosen by stakeholders and maintainers based on a few qualifications and customer response.
LTS releases are supported for three years after the initial release.
Current releases are supported for three months after a subsequent Current or LTS release.