C-Coupler2 is a new version of C-Coupler with a series of new enhancements. It is ready for use to develop various coupled or nested models. It has passed a number of test cases involving model coupling and nesting, and with various MPI process layouts between component models, and has already been used in several real coupled models. Its source code can be downloaded from https://github.com/C-Coupler-Group/c-coupler-lib.