diff --git a/.travis.yml b/.travis.yml
index ed95933..9a29f41 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,11 @@
 
 matrix:
   include:
+    - d: dmd-beta
+      env: [FRONTEND=2.071]
     - d: dmd
+      env: [FRONTEND=2.071]
+    - d: dmd-2.070.2
       env: [FRONTEND=2.070]
     - d: dmd-2.069.2
       env: [FRONTEND=2.069]
diff --git a/source/dub/internal/vibecompat/data/json.d b/source/dub/internal/vibecompat/data/json.d
index 16a24d3..c5bb7dd 100644
--- a/source/dub/internal/vibecompat/data/json.d
+++ b/source/dub/internal/vibecompat/data/json.d
@@ -25,8 +25,8 @@
 import std.datetime;
 import std.exception;
 import std.format;
-import std.string;
 import std.range;
+import std.string : format;
 import std.traits;
 
 version = JsonLineNumbers;
@@ -861,6 +861,8 @@
 Json parseJson(R)(ref R range, int* line = null, string filename = null)
 	if( is(R == string) )
 {
+	import std.string : startsWith;
+
 	Json ret;
 	enforceJson(!range.empty, "JSON string is empty.", filename, 0);
 
@@ -957,6 +959,8 @@
 */
 Json parseJsonString(string str, string filename = null)
 {
+	import std.string : strip;
+
 	auto strcopy = str;
 	int line = 0;
 	auto ret = parseJson(strcopy, &line, filename);
@@ -979,6 +983,8 @@
 }
 
 unittest {
+	import std.string : endsWith;
+
 	try parseJsonString(`{"a": 1`);
 	catch (Exception e) assert(e.msg.endsWith("Missing '}' before EOF."));
 	try parseJsonString(`{"a": 1 x`);