diff --git a/backend/tardigrade/fs.go b/backend/tardigrade/fs.go
index 371dbbfd5..490302866 100644
--- a/backend/tardigrade/fs.go
+++ b/backend/tardigrade/fs.go
@@ -1,4 +1,4 @@
-// +build go1.13,!plan9
+// +build !plan9
 
 // Package tardigrade provides an interface to Tardigrade decentralized object storage.
 package tardigrade
diff --git a/backend/tardigrade/object.go b/backend/tardigrade/object.go
index f7b31d78f..0f18e36dc 100644
--- a/backend/tardigrade/object.go
+++ b/backend/tardigrade/object.go
@@ -1,4 +1,4 @@
-// +build go1.13,!plan9
+// +build !plan9
 
 package tardigrade
 
diff --git a/backend/tardigrade/tardigrade_test.go b/backend/tardigrade/tardigrade_test.go
index 1ac3c3a12..90e966cff 100644
--- a/backend/tardigrade/tardigrade_test.go
+++ b/backend/tardigrade/tardigrade_test.go
@@ -1,4 +1,4 @@
-// +build go1.13,!plan9
+// +build !plan9
 
 // Test Tardigrade filesystem interface
 package tardigrade_test
diff --git a/backend/tardigrade/tardigrade_unsupported.go b/backend/tardigrade/tardigrade_unsupported.go
index 379c857a9..4b4f12137 100644
--- a/backend/tardigrade/tardigrade_unsupported.go
+++ b/backend/tardigrade/tardigrade_unsupported.go
@@ -1,3 +1,3 @@
-// +build !go1.13 plan9
+// +build plan9
 
 package tardigrade
diff --git a/cmd/mount/dir.go b/cmd/mount/dir.go
index 33ac660c2..cf83da13b 100644
--- a/cmd/mount/dir.go
+++ b/cmd/mount/dir.go
@@ -1,4 +1,4 @@
-// +build linux,go1.13 freebsd,go1.13
+// +build linux freebsd
 
 package mount
 
diff --git a/cmd/mount/file.go b/cmd/mount/file.go
index b182838a7..315ce7dff 100644
--- a/cmd/mount/file.go
+++ b/cmd/mount/file.go
@@ -1,4 +1,4 @@
-// +build linux,go1.13 freebsd,go1.13
+// +build linux freebsd
 
 package mount
 
diff --git a/cmd/mount/fs.go b/cmd/mount/fs.go
index 7f72634f7..78a99a6fc 100644
--- a/cmd/mount/fs.go
+++ b/cmd/mount/fs.go
@@ -1,6 +1,6 @@
 // FUSE main Fs
 
-// +build linux,go1.13 freebsd,go1.13
+// +build linux freebsd
 
 package mount
 
diff --git a/cmd/mount/handle.go b/cmd/mount/handle.go
index 7e35102c7..85bccba34 100644
--- a/cmd/mount/handle.go
+++ b/cmd/mount/handle.go
@@ -1,4 +1,4 @@
-// +build linux,go1.13 freebsd,go1.13
+// +build linux freebsd
 
 package mount
 
diff --git a/cmd/mount/mount.go b/cmd/mount/mount.go
index 5837512fc..88aac32de 100644
--- a/cmd/mount/mount.go
+++ b/cmd/mount/mount.go
@@ -1,6 +1,6 @@
 // Package mount implements a FUSE mounting system for rclone remotes.
 
-// +build linux,go1.13 freebsd,go1.13
+// +build linux freebsd
 
 package mount
 
diff --git a/cmd/mount/mount_test.go b/cmd/mount/mount_test.go
index ffc36212a..3a92fe076 100644
--- a/cmd/mount/mount_test.go
+++ b/cmd/mount/mount_test.go
@@ -1,4 +1,4 @@
-// +build linux,go1.13 freebsd,go1.13
+// +build linux freebsd
 
 package mount
 
diff --git a/cmd/mount/mount_unsupported.go b/cmd/mount/mount_unsupported.go
index e4284148d..a5a2c700e 100644
--- a/cmd/mount/mount_unsupported.go
+++ b/cmd/mount/mount_unsupported.go
@@ -1,13 +1,9 @@
 // Build for mount for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-// Invert the build constraint: linux,go1.13 freebsd,go1.13
-//
-// !((linux&&go1.13) || (freebsd&&go1.13))
-// == !(linux&&go1.13) && !(freebsd&&go1.13))
-// == (!linux || !go1.13) && (!freebsd || !go1.13))
+// Invert the build constraint: linux freebsd
 
-// +build !linux !go1.13
-// +build !freebsd !go1.13
+// +build !linux
+// +build !freebsd
 
 package mount
diff --git a/cmd/serve/ftp/ftp.go b/cmd/serve/ftp/ftp.go
index 92d59b0d9..a6e9f793b 100644
--- a/cmd/serve/ftp/ftp.go
+++ b/cmd/serve/ftp/ftp.go
@@ -1,6 +1,6 @@
 // Package ftp implements an FTP server for rclone
 
-//+build !plan9,go1.13
+//+build !plan9
 
 package ftp
 
diff --git a/cmd/serve/ftp/ftp_test.go b/cmd/serve/ftp/ftp_test.go
index 186b0fb34..3b7cba306 100644
--- a/cmd/serve/ftp/ftp_test.go
+++ b/cmd/serve/ftp/ftp_test.go
@@ -3,7 +3,7 @@
 //
 // We skip tests on platforms with troublesome character mappings
 
-//+build !windows,!darwin,!plan9,go1.13
+//+build !windows,!darwin,!plan9
 
 package ftp
 
diff --git a/cmd/serve/ftp/ftp_unsupported.go b/cmd/serve/ftp/ftp_unsupported.go
index 9cda63eb7..76b4b2ecf 100644
--- a/cmd/serve/ftp/ftp_unsupported.go
+++ b/cmd/serve/ftp/ftp_unsupported.go
@@ -1,7 +1,7 @@
 // Build  for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-// +build plan9 !go1.13
+// +build plan9
 
 package ftp