Recently the MS-900 exam received a very minor update that shouldn’t impact your preparation as it was only grammatical in nature.

Describe cloud concepts (5-10%)

Describe the different types of cloud services available

Describe the benefits of and considerations for using cloud, hybrid, or on-premises
services

Describe Microsoft 365 Apps and Services (45-50%)

Describe productivity solutions in Microsoft 365

Describe collaboration solutions in Microsoft 365

Describe endpoint modernization, management concepts, and deployment options in Microsoft 365

Describe analytics capabilities in Microsoft 365

Describe security, compliance, privacy, and trust in Microsoft 365 (25–
30%)

Describe identity and access management solutions of Microsoft 365

Describe threat protection solutions of Microsoft 365

Describe trust, privacy, risk, and compliance solutions of Microsoft 365

Describe Microsoft 365 Pricing, Licensing and Support (10-15%)

Plan, predict, and compare pricing

Identify licensing options available in Microsoft 365

Identify support options for Microsoft 365 services