It is NOT a sad fact that PHP is dropping the mysql interface that is filled with security holes.
Don't you mess up something? PHP extensions are not about mySQL interface. They are just bridges to connect to mySQL database and interface.
If mysql extension has security holes, then it's a sick point of PHP team. They have coded the buggy one bridge and instead of fixing it, they have produced another two with new bugs.
The script did not stop working two years ago when PHP announced it was dropping support. They have provided a couple of years for people to upgrade their scripts.
What kind of two years are you about?
C'mon, if you read these posts from StackOverflow
marked as posted in 2009, you will see very contrast opinions on that. Some quotes from there:
I have abandoned using mysqli. It is simply too unstable. I've had queries that crash PHP using mysqli but work just fine with the mysql package. Also mysqli crashes on LONGTEXT columns. This bug has been raised in various forms since at least 2005 and remains broken
What is better is PDO; it's a less crufty interface and also provides the same features as MySQLi.
Your opinion is just your opinion. It doesn't mean it's the right one.
I must add that the current mysql extension is being so popular because it's extermely simple and flexible. If we don't have object-oriented side in miniBB, then why we, or some other simple website, would need object-oriented extensions plugged in? If we are about SQL injections, then it's up to the coders themselves to provide the secured code. mysqli should not take care of somebody because of it.