In https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.5-Release-Notes they say:

SQL Script DataSource Initialization

The underlying method used to support schema.sql and data.sql scripts has been redesigned in Spring Boot 2.5. spring.datasource. properties related to DataSource initialization have been deprecated in favor of new spring.sql.init. properties. These properties can also be used to initialize an SQL database accessed via R2DBC.

In official documentation there are still used spring.datasource.*properties like url.

I think that release notes are not quite clear on this topic, and, AFAIU, spring.datasource.* properties like url, username, password, etc. have not been deprecated and should be used without changes. Otherwise, if there are new properties in spring.sql.init.* like url, password, etc., the documentation should be updated.

Comment From: wilkinsona

spring.datasource.* properties like url, username, password, etc. have not been deprecated and should be used without changes

That's correct.

The release notes attempt to describe this by saying the following as you've quoted above:

spring.datasource.* properties related to DataSource initialization

The key part of this is "related to DataSource initialization". spring.datasource.* properties like url, username, password are not related to DataSource initialization so they are not affected by the deprecation.

The spring.sql.init.* properties are described in the reference documentation. For reference, the same section in the 2.4.x documentation describes the old properties that have now been deprecated.