Inaccurate readings from Pedometer ++

I have been using this app for a couple of years now. It has always been great. But the last month it seems to be very inaccurate. I can walk the same path that I have walked previously and it is under reading. Usually, without fail, 10,000 steps gives me 5 miles. Now, Im lucky if it registers 4!! What is happening? Frustrated walker!!

MT walker about Pedometer++, v2.3.3