A tender addendum is an official change to a posted RFP, RFQ, or ITT issued before closing. It can extend the deadline, change drawings, or add a mandatory form. Bids that do not acknowledge all addenda are routinely disqualified. On Alberta portals (APC, MERX, Biddingo, city sites) you must download every addendum and follow the acknowledgement method in the instructions.
What addenda typically change
Closing time, quantities, specified products, insurance limits, and answers to bidder questions. Verbal answers at a pre-bid are not official until they appear in an addendum. If the owner says 'see addendum 3,' that document is part of the contract.
How do I acknowledge an addendum?
The form will say: a checkbox in the portal, a signed acknowledgement page, or a statement in the covering letter. Do all of the requested methods if more than one is listed.
What if an addendum drops two hours before close?
Read it. If you cannot comply, do not submit a non-compliant bid. Some owners extend close when changes are material; many do not.
Why alerts without reading still fail
A national $49.99-style alert may email that a tender exists. It will not tell you addendum 4 added COR. Government tender alerts for contractors only help if someone reads the documents. That is the difference between a raw feed and a monitoring retainer with go/no-go notes.
Which portal emails addenda?
Whichever portal you registered on for that bid. Registering on APC but bidding through a city email intake is how people miss files. Follow the issuing authority's instructions.
Can NorthCited watch addenda?
On retainers we watch matched opportunities through close. You still submit the bid.