After doing some updating to the boards and libraries via the Arduino IDE 2 things have happened:

• the Arduino generic function like Serial.print() have a squiggly line highlighting it as an unrecognised symbol but it compiles.
  

• sprint() and related functions stopped working for floating point numbers which is a pain as I use it to convert floating point numbers to formatted strings.
  

I've tried to remember what I upgraded and tried to rollback the changes but I was not successful.

Any ideas please?

Thanks for the report.

Have you restarted Atmel Studio, and re-built the sketch since performing the upgrades?

Otherwise please follow the guide in yellow above.