There are two corrections having been made in this releasing:

(1) 966 spectra observed during DR2 period (20111024 - 20140603) have been added into this version, of which the information are included in the list.

(2) Comparing to the previous DR3 internal releasing, the parameters are updated for 4,934,158 spectra in the following three aspects. Firstly, the classification results for 92 spectra are corrected after eye check. Secondly, the redshifts are recalculated for 1,190 spectra, mainly M-type. And thirdly, the errors of redshifts are changed for 4,934,010 spectra due to the modification of the error estimation method. We recalibrate the error of redshift by taking advantage of 13,942 targets with repeated observations. The details of updated information can be seen in the list.