Does anyone know how long Salesforce will continue support for JB4A-SDK-Android v4.5.0? (Since currently the SDK is deprecated)
v4.5 of the SDK was released in July 2016. What is/is not supported really comes down to the customer ask. Features clearly won't be ported back that far, but if there were a critical bug found, that had not already been corrected with an updated version of the SDK, it would be discussed and prioritized accordingly.
Is there a specific reason you're not upgrading to, at least, v5.4.4?