The wilcoxon function now computes the p-value for Wilcoxon’s signed rank test using the exact distribution for inputs up to length 25. The function has a new mode parameter to specify how the p-value is to be computed. The default is "auto", which uses the exact distribution for inputs up to length 25 and the normal approximation for larger inputs.
Just for posterity: these changes are to address changes to wilcoxon test approximation in scipy v1.5.0: https://docs.scipy.org/doc/scipy/reference/release.1.5.0.html