Sadly the iPhone app doesn't get updated. According to the app store version history:
v2.6.0 was released about 6 months ago, so around October 2023
v2.5.5 was released two years ago.
CBT Nuggets isn't much better.
A+, Network+, IT Fundamentals, Security+, Server+
MTA, MCSA Windows 10, MCSE Windows Server 2019
Security+, CASP, CEH, CISM, SSCP and CISSP
IT Service Managment
AWS, Amazon Web Services, Cloud Services
Topics related to Microsoft Azure
Topics surrounding to VMware vSphere and related products
GNU/Linux, Ubuntu, Red Hat and others
PMP, Prince2, SCRUM, and Agile