When did these changes come into effect?
The changes mentioned in the given context were made on various dates as follows:
1. 1-5-1960 (entry 7)
2. 1-11-1973 (entries 8, 10 and 14)
3. 1-11-2011 (entry 9)
4. 1-11-2000 (entries 11, 12 and 16)
5. 1-1-2007 (entry 13)
6. 31-10-2019 (entries 14 and 15)