What is 1% upgrade rule & how does it differ from 1% SIP hike?

The '1% upgrade' rule involved increasing the percentage of income invested by 1% yearly, while a 1% SIP increase involved increasing the investment by 1%. This means, for example, that a 1% upgrade will increase the ₹10,000 or 10% income invested to ₹11,000 or 11%, while a SIP hike will increase it to ₹10,100 (i.e. ₹10,000 + 1%).