update readme for version 4 beta.

Author: oshai

README.md

@@ -1,10 +1,7 @@
-# <img height="30" width="30" alt="kotlin-logging" src="https://raw.githubusercontent.com/oshai/kotlin-logging/master/misc/images/kotlin-logging.png"> [kotlin-logging](https://github.com/oshai/kotlin-logging) [![CI](https://github.com/oshai/kotlin-logging/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/oshai/kotlin-logging/actions/workflows/ci.yml) [![Slack channel](https://img.shields.io/badge/Chat-Slack-blue.svg)](https://kotlinlang.slack.com/messages/kotlin-logging/) [![Maven Central](https://img.shields.io/maven-central/v/io.github.microutils/kotlin-logging.svg)](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22io.github.microutils%22) [![Apache License V.2](https://img.shields.io/badge/license-Apache%20V.2-blue.svg)](https://github.com/oshai/kotlin-logging/blob/master/LICENSE)
+# <img height="30" width="30" alt="kotlin-logging" src="https://raw.githubusercontent.com/oshai/kotlin-logging/master/misc/images/kotlin-logging.png"> [kotlin-logging](https://github.com/oshai/kotlin-logging) [![CI](https://github.com/oshai/kotlin-logging/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/oshai/kotlin-logging/actions/workflows/ci.yml) [![Slack channel](https://img.shields.io/badge/Chat-Slack-blue.svg)](https://kotlinlang.slack.com/messages/kotlin-logging/) [![Maven Central](https://img.shields.io/maven-central/v/io.github.oshai/kotlin-logging.svg)](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22io.github.oshai%22) [![Apache License V.2](https://img.shields.io/badge/license-Apache%20V.2-blue.svg)](https://github.com/oshai/kotlin-logging/blob/master/LICENSE)
 
-Curious to try version 4? See https://github.com/oshai/kotlin-logging/issues/264 for details.
-
-## 
-
-Lightweight logging framework for Kotlin, written in [![Pure Kotlin](https://img.shields.io/badge/100%25-kotlin-blue.svg)](https://kotlinlang.org/).  
+Lightweight Multiplatform logging framework for Kotlin, written in 
+[![Pure Kotlin](https://img.shields.io/badge/100%25-kotlin-blue.svg)](https://kotlinlang.org/).  
 A convenient and performant logging facade.  
 For jvm `kotlin-logging` is wrapping [slf4j](http://www.slf4j.org/) with Kotlin extensions.  
 For other platforms `kotlin-logging` has various implementations. More details in the [wiki](https://github.com/oshai/kotlin-logging/wiki/Multiplatform-support)
@@ -41,7 +38,7 @@ logger.error(exception) { "a $fancy message about the $exception" }
 ## Getting started
 
 ```Kotlin
-import mu.KotlinLogging
+import io.github.oshai.KotlinLogging
 private val logger = KotlinLogging.logger {} 
 class FooWithLogging {
     val message = "world"
@@ -53,25 +50,54 @@ class FooWithLogging {
 
 An `Android` example project with kotlin-logging can be found in [kotlin-logging-example-android](https://github.com/oshai/kotlin-logging-example-android).
 
+## Version 4.x vs. previous versions
+
+Version 4 is still in beta but you're encourage to try it!  
+Version 4 is not backward compatible with previous versions.Group id (in maven) and packages names changed.
+It is possible to use both version 4 and previous versions side-by-side so some of the code from the old version
+and some new. It is also possible to have libs using old version and use the new version. In that sense it's
+a completely new dependency.
+
+Main changes are:
+- Maven group id changed from `io.github.microutils` -> `io.github.oshai`.
+- Root package change from `mu` -> `io.github.oshai`.
+- Slf4j dependency is not provided anymore (users have to provide it). It means that 4.x can work with both slf4j 1 or 2.
+- There are changes to multiplatform class hierarchy that might break compatibility.
+
+More details in issue [#264](https://github.com/oshai/kotlin-logging/issues/264).
+
 ## Download
 
 **Important note:** kotlin-logging depends on slf4j-api (in the JVM artifact). In runtime, it is also required to depend on a logging implementation. More details in [how-to-configure-slf4j](http://saltnlight5.blogspot.co.il/2013/08/how-to-configure-slf4j-with-different.html). And an excellent detailed explanation in [a-guide-to-logging-in-java](https://www.marcobehler.com/guides/a-guide-to-logging-in-java).  
+In version 4 users should also provide slf4j-api dependency.
 
 In short, if you just want to log statements to stdout, it's possible to add the following dependency: `org.slf4j:slf4j-simple:2.0.3`.
 
 ### Maven
 ```xml
+<dependency>
+  <groupId>io.github.oshai</groupId>
+  <artifactId>kotlin-logging-jvm</artifactId>
+  <version>4.0.0-beta-11</version>
+</dependency>
+```
+Or
+```xml
 <dependency>
   <groupId>io.github.microutils</groupId>
   <artifactId>kotlin-logging-jvm</artifactId>
-  <version>3.0.4</version>
+  <version>3.0.5</version>
 </dependency>
 ```
 See the full example in [kotlin-logging-example-maven](https://github.com/oshai/kotlin-logging-example-maven).  
 
 ### Gradle
 ```Groovy
-implementation 'io.github.microutils:kotlin-logging-jvm:3.0.4'
+implementation 'io.github.oshai:kotlin-logging-jvm:4.0.0-beta-11'
+```
+Or
+```Groovy
+implementation 'io.github.microutils:kotlin-logging-jvm:3.0.5'
 ```
 
 Alternatively, download the JAR from [github](https://github.com/oshai/kotlin-logging/releases/latest)  or [maven-central](https://repo1.maven.org/maven2/io/github/microutils/kotlin-logging/).