Fidelity Quirk: Mutual Funds Converted?

Fidelity Investments made an unusual change yesterday. Reviewing an investment portfolio we saw this:

At least some investors with holdings in FSEMX (Fidelity Spartan Extended Market Index fund) had them converted into a different symbol, FSEVX. We’ve noticed similar changes with two other funds.
FSIIX changed to FSIVX:

And F– USEX changed to FUSVX.

At first blush this appears to be only a symbol change. The names, share prices and values did not change. Transactions were denominated as $0.00.
This appears to be part of a change announced in December 2012. Some holders of Investor class funds are being upgraded to the Advantage class funds, which charge lower fees.
Still, we cannot find any current announcement from Fidelity nor any news stories about the change.
Here’s what Fidelity said back in December:
Why these changes?
The reduction of the expense ratio allows Fidelity to offer our customers some of the best priced index funds in the industry.
Lowering the investment minimums on the Investor and Fidelity Advantage® share classes, as well as changing the low balance fee, makes the funds accessible to more of our valued customers.
And the key language from that announcement:
For clients who will now qualify for the Fidelity Advantage® share class, the funds will automatically convert to the appropriate share class during our monthly updating process in January.
Affected funds might include:
Spartan 500 Index
Spartan Total Market Index
Spartan Mid-Cap Index
Spartan Small-Cap Index
Spartan Global ex U.S. Index
Spartan Emerging Markets Index
Spartan Real Estate Index
Spartan U.S. Bond Index
Note that FSIIX and FSIVX were not mentioned in that December announcement.
This appears to be a positive change for investors, but Fidelity could have done a better job communicating what it did.