@s{quotedtext}
@s{quotedtext}
You're running into the "very low priority transactions require a fee" rule. Priority depends on the value of the transaction (fewer bitcoins == lower priority) and how long ago you received the bitcoin(s) (older == higher priority).
That rule was in place for 0.3.20.2, but only for most miners. Most would not include very-low-priority transaction in blocks until they were old enough to have a high priority. The result was a big backlog of very-small transactions starting to build up.
With 0.3.21, the rules are the same for miners, for relaying transactions across the network, and for the user interface-- if your transaction is very-low-priority, it won't get relayed and the user interface will insist that you pay a fee if you really want it transmitted RIGHT NOW.
If you really really really need to send 0.01 bitcoins right now, then you'll have to pay the fee. If you're willing to wait a while, you'll find you can send it without a fee after it is old enough and has enough priority.
All of this is to discourage people from "penny flooding" -- constantly sending pennies back and forth to themselves without a fee just because they can.
Footnote: if you don't upgrade, you can send that 0.01 bitcoins without a fee. But as everybody else upgrades, you'll find that it will take a long time for that transaction to get confirmed.