If PayPal did change their fee rates for Micropayments, that wouldn't affect anything at our end, and we'd have no need to be informed of such a change. You should contact PayPal if you have any questions about their fees or policies. This appears to be their current Micropayments page:
Our only involvement in Micropayments is sending your order totals under $12 to checkout using a different PayPal Email that you have set up for Micropayments, if you'd entered that email in your E-junkie Seller Admin > Payment Preferences, rather than checking out with your regular PayPal Email entered in Admin > Edit Profile.
If all of your orders would qualify as Micropayments, then you might just consider converting your regular PayPal account to a Micropayments basis, and just set that as your regular PayPal Email in Admin > Edit Profile; in this case, there'd be no need to bother with our Micropayments PayPal Email setting, since you wouldn't need us to send orders over $12 to one account vs. under $12 to a different account, if all your orders are under $12 anyway.