If you change technology or the hotspot (WLAN -> 3G etc.) it is just natural to lose the IP and in effect lose your stream.
It should be possible to detect an IP address change and automatically re-initialize the streaming while the buffer of the former stream is still played.
Right now the app plays until the buffer runs empty and then restarts streaming, meaning a buffer size of 20 secs will cause a gap of 20 secs.
Customer support service by UserEcho