What actions should you take to keep the application secure?

To keep an application secure, regularly update software dependencies to patch vulnerabilities, implement strong authentication and authorization mechanisms, and use encryption for data in transit and at rest. Conduct regular security audits and penetration testing to identify and fix potential weaknesses. Additionally, employ input validation and sanitization to prevent common attacks like SQL injection and cross-site scripting. Lastly, educate your team on security best practices to foster a security-aware culture.