This ISR describes a number of improvements to calnica, the STSDAS task that performs routine instrumental calibration of NICMOS raw images. We report two major and a number of minor updates to the code. The major updates consist of changes in the way the count rate is calculated from up-the-ramp fitting and changes in the cosmic rays rejection algorithm. All updates have been extensively tested and analysis shows improvement in the S/N of output images by 6-15% compared to the previous calnica version. A further improvement is that the error extension in the calibrated images now represents the true errors in a more consistent way compared to the old implementation