Official Documentation for IBM i 7.5, where you can find information about how to install, maintain, and use the IBM i. 7.5 is the current release, delivered in 2022.
This IBM Support web page is where you can start for more information about IBM i OpenSSH and OpenSSL.
This IBM Redbook includes several of the announced features for SQL procedures, triggers, and functions in IBM i versions 6.1, 7.1, and 7.2.
This IBM Redpaper publication provides a broad overview and understanding of Db2 Mirror for i by covering its architecture, positioning, planning, and implementation aspects.
This IBM Redbook publication is focused on helping the IBM i development community understand the modern RPG language.