README.md: update API requirement to Java 8 or Android 6
@@ -10,7 +10,7 @@ The bitcoinj library is a Java implementation of the Bitcoin protocol, which all
### Technologies
-* Java 8+ (Java 7 API, Java 8 bytecode) and Gradle 4.4+ for the `core` module
+* Java 8+ (needs Java 8 API or Android 6.0 API, compiles to Java 8 bytecode) and Gradle 4.4+ for the `core` module
* Java 8+ and Gradle 4.4+ for `tools` and `examples`
* Java 11+ and Gradle 4.10+ for the JavaFX-based `wallettemplate`
* [Gradle](https://gradle.org/) - for building the project
