Abstract: A system and method of performing communications over a communications network that uses a communication protocol having multiple different versions, provides for backwards compatibility when devices that support a higher or more secure version of the communication protocol are added to a network having devices that only support a lower or less secure version of the communication protocol. The system and method includes a technique of negotiating and establishing security procedures to be implemented in a communication connection between two devices on the network based on initial session request messages that indicate the version of the communication protocol supported by one or both of the devices. This system and method enable higher and lower protocol version devices (i.e.

Abstract: A digital safety lock of a field device or other process plant equipment activates in response to receiving a request from a locking party, thereby placing the device into a locked mode. While the device is in the locked mode, only the locking party may perform maintenance activities on, or otherwise functionally control, the device. While locked, the device may provide an indication of the locking party to any other device or application attempting to access or control the locked device. Other devices, applications, and users may communicate with the locking party or locking party device to request that the device be unlocked and/or to request the corresponding digital safety lock key. Upon the device receiving the correct digital safety lock key, the digital safety lock may be deactivated, and the device may enter into an unlocked state if no other digital safety locks remain activated for the device.