You can find the announcement here, but it is short enough to quote:
We are happy to announce that all pilots who had Aurum balances outstanding from the PLEX changes have now had their converted PLEX balances delivered as of downtime May 23rd.
In order to protect the market and value of PLEX during the transition, all pilots who had less than 1000 Aurum in their wallets did not have this converted to PLEX when the changes were deployed on May 9th, and were notified that they would receive their Aurum balance in PLEX three months after the deployment of the PLEX changes.
After careful consideration and close monitoring of the market, we have decided to reimburse these PLEX earlier.
Today’s daily downtime was extended slightly in order to allow for a reimbursement script to be run, and all pilots should now have their outstanding PLEX balances reimbursed.
As it turned out, the market did not need much in the way of protection. The price of 500 new PLEX (needed for the 30 days of game time that a single old PLEX would grant) went up after the conversion and has remained up. This wasn’t all that surprising to me. It seemed akin to a 500 for 1 stock split, and the price of a stock almost always goes up after such a change. (If it doesn’t, you shouldn’t have done the split.) And new PLEX can be used for more things (even if character transfers are no longer on the list) so more demand, and an accompanying rise is price, seemed likely.
That means ISK is effectively cheaper if you want to sell PLEX. If you are buying PLEX to pay for your null sec Rorqual mining alts in the face of nerfs and low mineral prices however, this might be a painful time. I will be interested to see what the monthly economic report for May and June will show.
Anyway, I will have to check in and see if I have 42 more PLEX on the accounts that had the 300 gift PLEX.