Origins: Shared Foundations, Separate Development
Project V is an open-source technology ecosystem for proxy communication, routing, and transport. V2Ray is one of its widely used projects. V2Fly continues community development of a related core, while Xray has grown from a shared codebase into a separate lineage. Neither is simply an older or newer replacement for the other: they share many configuration concepts, but supported fields, extensions, and default behavior can differ as each project evolves.
What the Core Does: Connections, Not the Entire Interface
A graphical client turns subscriptions and settings into a configuration the core can execute. The core establishes protocol connections, applies routing, and handles outbound traffic. That’s why two servers labeled VLESS may still require different implementations depending on their transport, security settings, or extension fields. For settings such as REALITY, first confirm that the selected core supports them, then enter the public key, server name, and other values provided by the server source.
Open Source: Check Each Project’s License
v2rayN, v2rayNG, and v2flyNG are open-source clients, but their interface and core code may use different licenses. The v2rayN and v2rayNG client projects use GPL-3.0; the V2Fly and Xray core projects use MPL-2.0. When using, modifying, or redistributing software, refer to the license included with the relevant release package. Don’t assume one license applies to every dependency.
Updates: Client, Core, and Subscription
Client updates change the interface and configuration management; core updates affect protocol capabilities; subscription updates refresh server settings. These are three different things. A successful subscription update won’t add missing core features, and upgrading the app won’t replace expired server credentials. Back up groups and custom rules before updating, then retest the connection and routing using the same steps as before. This makes compatibility changes easier to spot than changing everything at once.