The previous version of the TFTP specification, RFC 783, included the following statement:
All packets other than those used for termination are acknowledged individually unless a timeout occurs.
The new specification revises this as follows:
All packets other than duplicate ACKs and those used for termination are acknowledged unless a timeout occurs.
The change was made to fix a problem referred to as the "Sorcerer's Apprentice." Deduce and explain the problem.