Cumulative updates:
SSH/SFTP extensions issue fixed (caused negotiation errors)
SSH/SFTP rsa key-pair issues using sha2-256/512 fixed
SSH/SFTP ecdsa key-pair issues fixed
Additional checks for SFTP key exchange (corruption)
ECDH/Curve25519 updates
2.21 had issues with DH group1-sha1. Please discard that version.