“Your Flash Player may be out of date. Please update to continue…” such type of fake update messages are used to infect computer systems with unwanted software.
Kindly ignore such messages if you find something suspicious, or try to install updates from authorized site.
If you click on Agree and Install, it will redirect you to a link which will download malicious setup.
If you suspect your computer may be infected with malware, it is recommended to run a full system scan with NPAV. Make sure you have updated and renewed your NPAV Antivirus software to stay protected from such attacks also check that you have activated Anti Phishing, Email Scanner, Website blocker and other features of NPAV.