The Defense Security Cooperation Agency notified Congress January 13 of a possible Foreign Military Sale to Singapore for an upgrade of F-16 Block 52 aircraft and associated equipment, parts, training and logistical support for an estimated cost of $2.43 billion. More at the DSCA's website.
The notification is for 60 aircraft, i.e. Singapore's entire F-16 fleet. I should have an in-depth look at this latest development up in the next few days