diff --git a/vendor/github.com/prometheus/common/expfmt/expfmt.go b/vendor/github.com/prometheus/common/expfmt/expfmt.go
index 371ac750..c71bcb98 100644
--- a/vendor/github.com/prometheus/common/expfmt/expfmt.go
+++ b/vendor/github.com/prometheus/common/expfmt/expfmt.go
@@ -26,7 +26,7 @@ const (
 
 	// The Content-Type values for the different wire protocols.
 	FmtUnknown      Format = `<unknown>`
-	FmtText         Format = `text/plain; version=` + TextVersion
+	FmtText         Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
 	FmtProtoDelim   Format = ProtoFmt + ` encoding=delimited`
 	FmtProtoText    Format = ProtoFmt + ` encoding=text`
 	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
diff --git a/vendor/vendor.json b/vendor/vendor.json
index a147c7b2..e2681492 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -133,34 +133,34 @@
 			"revisionTime": "2017-11-17T10:05:41Z"
 		},
 		{
-			"checksumSHA1": "xfnn0THnqNwjwimeTClsxahYrIo=",
+			"checksumSHA1": "+wZ+Pa6NX+NOxUvayXBXGOcqFe8=",
 			"path": "github.com/prometheus/common/expfmt",
-			"revision": "89604d197083d4781071d3c65855d24ecfb0a563",
-			"revisionTime": "2018-01-10T21:49:58Z"
+			"revision": "38c53a9f4bfcd932d1b00bfc65e256a7fba6b37a",
+			"revisionTime": "2018-03-26T16:04:09Z"
 		},
 		{
 			"checksumSHA1": "GWlM3d2vPYyNATtTFgftS10/A9w=",
 			"path": "github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg",
-			"revision": "89604d197083d4781071d3c65855d24ecfb0a563",
-			"revisionTime": "2018-01-10T21:49:58Z"
+			"revision": "38c53a9f4bfcd932d1b00bfc65e256a7fba6b37a",
+			"revisionTime": "2018-03-26T16:04:09Z"
 		},
 		{
 			"checksumSHA1": "MGnqHnmEqc1fjnYiWReSiW8C27A=",
 			"path": "github.com/prometheus/common/log",
-			"revision": "89604d197083d4781071d3c65855d24ecfb0a563",
-			"revisionTime": "2018-01-10T21:49:58Z"
+			"revision": "38c53a9f4bfcd932d1b00bfc65e256a7fba6b37a",
+			"revisionTime": "2018-03-26T16:04:09Z"
 		},
 		{
 			"checksumSHA1": "YU+/K48IMawQnToO4ETE6a+hhj4=",
 			"path": "github.com/prometheus/common/model",
-			"revision": "89604d197083d4781071d3c65855d24ecfb0a563",
-			"revisionTime": "2018-01-10T21:49:58Z"
+			"revision": "38c53a9f4bfcd932d1b00bfc65e256a7fba6b37a",
+			"revisionTime": "2018-03-26T16:04:09Z"
 		},
 		{
 			"checksumSHA1": "91KYK0SpvkaMJJA2+BcxbVnyRO0=",
 			"path": "github.com/prometheus/common/version",
-			"revision": "89604d197083d4781071d3c65855d24ecfb0a563",
-			"revisionTime": "2018-01-10T21:49:58Z"
+			"revision": "38c53a9f4bfcd932d1b00bfc65e256a7fba6b37a",
+			"revisionTime": "2018-03-26T16:04:09Z"
 		},
 		{
 			"checksumSHA1": "Etvt6mgzvD7ARf4Ux03LHfgSlzU=",