How many bytes can I send in a UDP packet with a V16Pro or V4Pro?

For V16Pro Model S, V16Pro & V4Pro, 
The maximum UDP data payload size currently set to 1490.

For the entire UDP packet, including bytes for Ethernet or UDP header information, can be up to 1518 bytes.

Note: if the device is TCP, it's setup as a 'stream' and will split the packet as needed to send entire message. 

For incoming messages (TCP or UDP), the maximum size to parse with the product files (regular expressions) at one time is 1040.