Replication steps :
1) Open the dashboard
2)Click on create document template
3) check Does this form required an expiration date?
4) Enter "Valid from" and "Valid to" date manually eg : 05/05/1990
5)Then open the date picker, in year only upto 20 years are seen eg from 1980-2000

Expected : When year is changed manually or through date picker, all the years should be listed . there should not be restrictions of upto 20 years