(still) going strong
Continuing to be healthy, successful, or function properly. Smartphones are designed to become obsolete, but my old flip phone from 2004 is still going strong. My great-grandfather is 94 and going strong to this day!
go strong
To proceed energetically or successfully. Grandpa is such an inspiration—he's 92 and still going strong with a more active social life than I have! Our marketing campaign is going strong this quarter, so I'm expecting a big bump in sales.
Going strong
functioning well or energetically. We are still well and going strong.
going strong
continuing to be healthy, vigorous, or successful. informal