Submitted by: @pavel-zotov

Prepare and run this script on 4.0:

set bail on;
set list on;
set echo on;
select * from mon$attachments where mon$attachment_id = current_connection;
show table mon$attachments;
show version;

Redirect its output to log and then do:
findstr /i /c:"MON$WIRE_" file.log

You will see only 2 lines instead of expected 4:
MON$WIRE_COMPRESSED <true>
MON$WIRE_ENCRYPTED <false>

Command "SHOW TABLE ..." does not produce fields related to wire compression and encryption.