diff --git a/.travis.yml b/.travis.yml
index 156fb86..93d402f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,6 @@ group: edge
 language: php
 
 php:
-  - 7.0
   - 7.1
   - 7.2
   - nightly
diff --git a/README.md b/README.md
index 22e8051..8154a17 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,10 @@ This PHP extension provides a set of useful functional-style operations on PHP a
 
 Method names and functionalities are inspired by [Kotlin.Collections](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/).
 
+### 1.1 Notes
+
+* This extension requires PHP 7.1 and above.
+
 ## 2. Documentation
 
 ### 2.1 Functionalities