No, ProsodyS v3 applications cannot assume a single instance of Prosody S.
Several instances of Prosody S v3 can be run on separate PCs, all controlled or accessible from a single application host, in a manner very similar to Prosody X.
Therefore, it is important that applications scan through the list of available 'cards', taken from an acu_get_system_snapshot() and check each one for being a Prosody S v3 instance.
Also, due to the multiple instance capability of ProsodyS v3, it cannot be assumed that Prosody S v3 is identifiable via the serial number/name "HS_PROSODYS_S". When a ProsodyS v3 instance is added via the ACT it must be given a unique user defined serial name/number.
It is therefore recommended, for general use, that applications do not use "HS_PROSODYS" as a means of identifying either ProsodyS v2 or ProsodyS v3 but instead use the card types as mentioned earlier.
Please also note that for applications that are to utilise multiple remote Prosody S v3 instances, there is no built in Aculab API mechanism to switch traffic between these instances - it is an application's responsibility to manage the connections between instances and utilise whatever solutions are most appropriate. Examples would include SIP re-INVITEs or setting up Prosody S to Prosody S RTP streams.