WebSockets have come a long way since their introduction in 2011, but they still face compatibility issues with some browsers, firewalls, and proxies. While most modern systems support WebSockets, there are still edge cases where connections can fail due to outdated antivirus software, network providers, or strict security settings. Libraries like Socket.IO and SignalR provide HTTP fallbacks as a solution, but scaling these alternatives can be complex and time-consuming. Developers building realtime features with Ably can benefit from maximum compatibility and efficiency without worrying about backend infrastructure.