diff --git a/go.mod b/go.mod
index d405f77..e1b1a2d 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module git.metabarcoding.org/lecasofts/go/obitools
 
-go 1.18
+go 1.20
 
 require (
 	cloudeng.io/algo v0.0.0-20230314235058-45ee90f9cff7
@@ -18,6 +18,7 @@ require (
 )
 
 require (
+	github.com/daichi-m/go18ds v1.12.1 // indirect
 	github.com/klauspost/compress v1.16.3 // indirect
 	github.com/mattn/go-runewidth v0.0.14 // indirect
 	github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db // indirect
diff --git a/go.sum b/go.sum
index b66334b..1174378 100644
--- a/go.sum
+++ b/go.sum
@@ -18,6 +18,8 @@ github.com/PaesslerAG/jsonpath v0.1.0 h1:gADYeifvlqK3R3i2cR5B4DGgxLXIPb3TRTH1mGi
 github.com/PaesslerAG/jsonpath v0.1.0/go.mod h1:4BzmtoM/PI8fPO4aQGIusjGxGir2BzcV0grWtFzq1Y8=
 github.com/barkimedes/go-deepcopy v0.0.0-20220514131651-17c30cfc62df h1:GSoSVRLoBaFpOOds6QyY1L8AX7uoY+Ln3BHc22W40X0=
 github.com/barkimedes/go-deepcopy v0.0.0-20220514131651-17c30cfc62df/go.mod h1:hiVxq5OP2bUGBRNS3Z/bt/reCLFNbdcST6gISi1fiOM=
+github.com/daichi-m/go18ds v1.12.1 h1:Pjc3IApmN4qtDiovGP9MvMpIzgZle3SHUcNaA5j46bg=
+github.com/daichi-m/go18ds v1.12.1/go.mod h1:wc2dURUr8aMxxC4Mn5ObJGVM7uIKU8JagY4nhtonXq8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=