# Welcome
**Here are SkyWalking 6 official documents. Welcome to join us**

From here you can learn all about **SkyWalking**’s architecture, how to deploy and use SkyWalking, also develop based on SkyWalking.

- [Concepts and Designs](en/concepts-and-designs/README.md). Concepts and designs explain the most important core ideas about
SkyWalking. You can learn from here if you want to understand what is going on under our cool features and visualization.
- [Setup](en/setup/README.md). Setup contains guides for installing SkyWalking in different scenarios. As a platform, it provides
several ways to provide observability, including monitoring and alarm of course. 
- [Contributing Guides](en/guides/README.md). Guides are for PPMC, committer or new contributor. At here, you can know how to contribute from beginning.
- [Protocols](en/protocols/README.md). Protocols show the communication ways between agents/probes and backend. Anyone, interested
in uplink telemetry data, definitely should read this.
- [FAQs](en/FAQ/README.md). Include a manifest, including already known setup problems, secondary developments experiments. When 
you are facing a problem, check here first.


In addition, you might find these links interesting:

- The latest and old releases are all available at [Apache SkyWalking release page](http://skywalking.apache.org/downloads/). The change logs are [here](../CHANGES.md).
- You can find the speaking schedules at Conf, online videos and articles about SkyWalking in [Community resource catalog](https://github.com/OpenSkywalking/Community).
Also, if you have some related to us, welcome to submit a pull request to add.
- We’re always looking for help improving our documentation and codes, so please don’t hesitate to [file an issue](https://github.com/apache/incubator-skywalking/issues/new) 
if you see some problem. 
Or better yet, submit your own contributions through pull request to help make them better.

For documents in other languages, contributed by our community.
- [中文 :cn:](others/cn/README.md)

___
### Users from 5.x
SkyWalking 5.x is still supported by the community. For the user plans to upgrade from 5.x to 6.x, you should know there are some definitions of concepts changed.

The most important two changed concepts are
1. Application(in 5.x) is changed to **Service**(in 6.x), also Application Instance is changed to **Service Instance**.
1. Service(in 5.x) is changed to **Endpoint**(in 6.x).


