You should NOT alert
All bids above 3NT except for Artificial Opening Bids and Lightner doubles
Bids of 1♣ or 1♦ that may be as short as 3 cards (but not shorter)
Sputnik/Negative doubles no longer need to be alerted (as their use has become the norm)
The straight forward Stayman 2♣ bid or its responses
A weakness take-out response of 2 of any suit to partner’s opening 1NT
The initiation or completion of simple Red Suit Transfers (eg when partner’s 2♦ or 2♥ response to 1NT is a transfer, that bid and the opener’s 2♥ or 2♠ bid should not be alerted)
Opening 2 level bids which proclaim a single suit but are weak (eg a Benji 2♥
You will need to ANNOUNCE partner’s bid in the following situations
When partner bids 1NT partner immediately announces the strength by stating eg ‘12-14’ and adding if applicable ‘possible singleton’
In the straightforward Stayman sequence 1NT-2♣ Opener simply says ‘Stayman’
In the case of Red suit Transfers where 2♦
When Playing Basic Acol the strong Natural Opening Bids of 2♥ and 2♠.
When playing other Systems involving weak 2’s (eg Benji) the Opening Bids of 2♥, 2♠ (or even 2♦) would be announced by Partner as ‘Weak‘
When playing Precision the opening bid of 2♣ should be announced as ‘Intermediate’
You should not alert a double if it is
A double of a natural or semi -naturalsuit. In the absence of an Alert this is deemed to be for Take-out.
A double of a short nebulous, prepared, or phony minor Opening Bid. In the absence of an Alert this is again deemed to be for Take out.
A penalty double of a No Trump bid.
A penalty/lead directing double of a suit Bid that does not show that suit (so for example doubles of a strong 1♣,Stayman 2♣ and Transfer bids show the suit doubled in the absence of an alert).
This summary of the changes is based on an article by Mike Swanson, whose assistance in preparing this one page Guide to the changes is gratefully acknowledged.