Below are the risk factors involved:
1. Future WAAE releases may not support the compatibility with legacy agents.
2. The legacy agent release may already be "End Of Life" or "End Of Support"
3. User have to disable Instance-wide encryption to configure legacy agent with r11.3.6 release scheduler
4. CA AutoSys r4.5 agents uses Data Encryption Standard [DES48] encryption which has been deprecated.