In 2015, the SERE conference (IEEE International Conference on Software Security and Reliability) and the QSIC conference (IEEE International Conference on Quality Software) were combined into a single conference, QRS, with Q representing Quality, R for Reliability, and S for Security, sponsored by the IEEE Reliability Society. This conference provides engineers and scientists from both industry and academia a platform to present their ongoing work, relate their research outcomes and experiences, and discuss the best and most efficient techniques for the development of reliable, secure, and trustworthy systems. It also represents an excellent opportunity for the academic community to become more aware of subject areas critical to the software industry as practitioners bring their needs to the table. The 21st QRS conference will be held from December 6-10, 2021 in Hainan Island, China.