diff --git a/module/apmfasthttp/closer.go b/module/apmfasthttp/closer.go
index c2c4a4aa7..73dcdd57d 100644
--- a/module/apmfasthttp/closer.go
+++ b/module/apmfasthttp/closer.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 import (
diff --git a/module/apmfasthttp/consts.go b/module/apmfasthttp/consts.go
index 4c8b31c7e..a3505ac69 100644
--- a/module/apmfasthttp/consts.go
+++ b/module/apmfasthttp/consts.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 const txKey = "apmfasthttp_transaction"
diff --git a/module/apmfasthttp/context.go b/module/apmfasthttp/context.go
index b6c843c7a..5936cea48 100644
--- a/module/apmfasthttp/context.go
+++ b/module/apmfasthttp/context.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 import (
diff --git a/module/apmfasthttp/doc.go b/module/apmfasthttp/doc.go
index 37c3f48f3..6dc5f5d7e 100644
--- a/module/apmfasthttp/doc.go
+++ b/module/apmfasthttp/doc.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 // Package apmfasthttp provides a tracing middleware fasthttp.RequestHandler for
 // servers.
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
diff --git a/module/apmfasthttp/recovery.go b/module/apmfasthttp/recovery.go
index 308fa44a9..e9e637627 100644
--- a/module/apmfasthttp/recovery.go
+++ b/module/apmfasthttp/recovery.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 import (
diff --git a/module/apmfasthttp/server.go b/module/apmfasthttp/server.go
index dfb2381c1..627a751dc 100644
--- a/module/apmfasthttp/server.go
+++ b/module/apmfasthttp/server.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 import (
diff --git a/module/apmfasthttp/types.go b/module/apmfasthttp/types.go
index b32286a63..76d08c3e4 100644
--- a/module/apmfasthttp/types.go
+++ b/module/apmfasthttp/types.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 import (
diff --git a/module/apmfasthttp/utils.go b/module/apmfasthttp/utils.go
index 1e0a2f985..6802ccf19 100644
--- a/module/apmfasthttp/utils.go
+++ b/module/apmfasthttp/utils.go
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+// +build go1.12
+
 package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
 
 import (