diff --git a/pkg/obioptions/version.go b/pkg/obioptions/version.go
index 2ac8e39..ff88eaf 100644
--- a/pkg/obioptions/version.go
+++ b/pkg/obioptions/version.go
@@ -8,7 +8,7 @@ import (
 // corresponds to the last commit, and not the one when the file will be
 // commited
 
-var _Commit = "0067152"
+var _Commit = "573acaf"
 var _Version = "Release 4.2.0"
 
 // Version returns the version of the obitools package.
diff --git a/pkg/obitools/obiconvert/sequence_writer.go b/pkg/obitools/obiconvert/sequence_writer.go
index 01f964b..9198082 100644
--- a/pkg/obitools/obiconvert/sequence_writer.go
+++ b/pkg/obitools/obiconvert/sequence_writer.go
@@ -21,7 +21,7 @@ func BuildPairedFileNames(filename string) (string, string) {
 	forward := parts[0] + "_R1"
 	reverse := parts[0] + "_R2"
 
-	if parts[1] != "" {
+	if len(parts) > 1 && parts[1] != "" {
 		suffix := "." + parts[1]
 		forward += suffix
 		reverse += suffix