Techniques for supporting positioning for terminals in a wireless network are described. In an aspect, a message is prepared and transmitted with a message segment including a version of a protocol used to encode the message and a compatibility level associated with inter-operable protocol versions, wherein different compatibility levels indicate non-compatibility between protocol versions. In another aspect, a message is received with a message segment including a version of a protocol used to encode the message and a compatibility level associated with inter-operable protocol versions, wherein different compatibility levels indicate non-compatibility between protocol versions. The compatibility level included in the received message is compared to an internal compatibility level and a response message is prepared and transmitted with a message segment including the internal compatibility level.