How can I create and maintain a connection status for Input/Output?

Open the process in the detailed graphic view. If you then click on the desired edge between input/output and the process task (1), a "Connection status" field appears in the Detail Content.
 
Here you enter the desired term / designation (2) and then update the graphic (3).
 
 

 
 
The term entered then appears at the edge of the input/output (4). This can only be seen in the detailed graphic view.

 This "connection status"-Information then also appears in the Detail Content at the respective object.
 

 
and in the new standard subprocess manual (if this is not yet installed on your system, you can find the corresponding instructions here) in chapter "Interactions between processes and business objects".

If you maintain Symbio in multiple languages, the connection status must be maintained separately in each language at this time.

To delete the Connection Status:

If you do not want this content on the edges, you can simply delete it using the method described at point (2) but deleting the existing content instead of writing a new one and then update the graphic. Important - for multilingual models, this only works in the language in which the "Connection status"-Information was created.