Size of data packets in SSH connection

[david kohn7]

Hello,
During an interactive connection (i.e past the login), is it true that all
data packets (i.e data size of the packet excluding the TCP/IP headers)
must be a multiple of 4? or it can it be odd? If so , will the other end
hang up?

Can it change during the connection?
Is it also true for non interactive connections such as scp,sftp ?


Thanks
DK