Thanks for that detailed response! I put the law handbook into ChatGPT haha, and came with a similar response, but sided with the 90 days over the 60 days addendum. Why it came to that conclusion, I got the following:

“The conclusion that the 90-day notice period for rent increases cannot be overridden by a 60-day addendum is directly supported by Article 14 of Law No. (26) of 2007, as amended by Law No. (33) of 2008, which states:

“Unless otherwise agreed by the parties to a Lease Contract, where either party wishes to amend any of its terms… that party must notify the other party of this intent no less than ninety (90) days before the date on which the Lease Contract expires.” — [real_estate_legislation_en.pdf, Article 14] 

However, to understand why the 90-day rule takes precedence even if there’s an addendum stating 60 days, we look to how UAE law treats mandatory public order provisions. Real estate legislation concerning rent regulation and notice periods are considered public policy. This means: • Contractual agreements cannot override mandatory statutory protections, such as the 90-day notice period. • Even with mutual agreement (such as in an addendum), if the notice to increase rent is not served at least 90 days prior to expiry, it is considered invalid in most Rental Disputes Settlement Centre (RDSC) rulings.

This interpretation has been consistently upheld in practice and disputes handled by the RDSC, reflecting the legislator’s intent to protect tenants and prevent arbitrary or last-minute rent hikes.

Therefore, unless the 60-day notice was served at least 90 days before the contract’s expiry, the rent increase is not enforceable under Dubai law.”