[werk_ag]

Locate the SHT1X.cpp file in your libraries folder.
Open it with a text editor like Notepad++.
Change to this:

Code:

// Conversion coefficients from SHT15 datasheet
  // V3 Sensors
  const float C1 = -4.0;       // for 12 Bit
  const float C2 =  0.0405;    // for 12 Bit
  const float C3 = -0.0000028; // for 12 Bit

  // V4 Sensors
  //const float C1 = -2.0468;       // for 12 Bit
  //const float C2 =  0.0367;       // for 12 Bit
  //const float C3 = -1.5955E-6;    // for 12 Bit

Edited: Forgot to say, you have to reprogram the TX unit again.