Serial echo for 433Mhz RF transmitter

So The fix is?

Go to the directory where the reference information is stored on your computer. Delete the folder where the String documentation is stored, and forget that such a resource wasting class exists. People have been writing text handling applications using C strings for more than 40 years. The crutches provided by the String class are simply not needed. Learn to use NULL terminated char arrays, and save yourself a ton of grief.