In September 2020, a new law went into effect that considerably shortened the period of probation for most crimes.
Prior to AB 1950 most misdemeanors carried probation periods of 3-5 years, and most felonies had probationary periods for 5 years. AB 1950 has changed all that.
Now for the most part the maximum probation period on a misdemeanor is 1 year. For most felonies, the maximum probation period is 2 years.
The exception to the above rules is when the particular crime carries a specific probationary period, which is indicated in the law.
However, for those who are already on probation, and benefit from this law, it is not automatic that the probation period is diminished. You must, in fact, petition the Court for a termination of your probation.