Is create-next-app@rc installing the latest Next.js 15 version available?

* create-next-app@latest installs the latest nextjs version 14.2.5 (10 July)
* create-next-app@rc installs the latest nextjs rc version 15.0.0-rc.0 (23 May)
* create-next-app@canary installs the latest nextjs canary version 15.0.0-canary.123 (21 August) (at the time of writing).

Although 14.2.5 is more recent than 15.0.0-rc.0, 14.2.* are mainly security patches so you still have more updated code in 15.0.0-rc.0.

When will the stable versions of Next.js 15 and React 19 be available?

We don't know, there is no roadmap.

What is the correct way to install Next.js with Bun, and does Bun really make Next.js apps faster?

This has all the answers you need: https://bun.sh/guides/ecosystem/nextjs