go.mod  | 2 +-
 go.sum  | 6 ++----
 main.go | 6 +++---

diff --git a/go.mod b/go.mod
index 65e493a2211fa6df906503b0bf098a097b43680f..823be12b9bbdf4c8bc2ad57adc510dd39c0ade3a 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ toolchain go1.22.5
 
 require (
 	go.cypherpunks.su/recfile/v2 v2.0.0
-	go.cypherpunks.su/tai64n/v3 v3.0.0
+	go.cypherpunks.su/tai64n/v4 v4.1.0
 	golang.org/x/net v0.21.0
 	lukechampine.com/blake3 v1.3.0
 )
diff --git a/go.sum b/go.sum
index 174a39fd118f2baddef1e4a6dea71730725394f1..24c132538cdb1fc79777142c4b33942ba861a9a8 100644
--- a/go.sum
+++ b/go.sum
@@ -2,10 +2,8 @@ github.com/klauspost/cpuid/v2 v2.2.8 h1:+StwCXwm9PdpiEkPyzBXIy+M9KUb4ODm0Zarf1kS5BM=
 github.com/klauspost/cpuid/v2 v2.2.8/go.mod h1:Lcz8mBdAVJIBVzewtcLocK12l3Y+JytZYpaMropDUws=
 go.cypherpunks.su/recfile/v2 v2.0.0 h1:Q2o+OzM1H2O1WnshU88r+waBqylkqZj8plBdBWZitcU=
 go.cypherpunks.su/recfile/v2 v2.0.0/go.mod h1:36EnyBwx6VpsSM5MMcYGTDiKrVEP49S09p33EFuhQYU=
-go.cypherpunks.su/tai64n/v3 v3.0.0 h1:JvQiZJwkswUttMNcPrYS4KUK9Zfl6xllD0N6ZnSZX/U=
-go.cypherpunks.su/tai64n/v3 v3.0.0/go.mod h1:zGDFuyiFKJk+iem8lyBaFeCm+MNMOn7RRWy456n1J78=
-golang.org/x/crypto v0.19.0 h1:ENy+Az/9Y1vSrlrvBSyna3PITt4tiZLf7sgCjZBX7Wo=
-golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
+go.cypherpunks.su/tai64n/v4 v4.1.0 h1:jW0EyklKXpSy9DSFMcDbu7XuLlMkn6kkpNWiMG6UT5c=
+go.cypherpunks.su/tai64n/v4 v4.1.0/go.mod h1:/uKUdhLOy8UciRKpapPaFXSOoa/SiXjs3XsDDpAz7OA=
 golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
diff --git a/main.go b/main.go
index 77f617d76871fba1b88330cde068cbcda1c61e93..98869ef2106282c5fc2f6e7c14e37af979659a1b 100644
--- a/main.go
+++ b/main.go
@@ -36,7 +36,7 @@ 	"sync"
 	"time"
 
 	"go.cypherpunks.su/recfile/v2"
-	"go.cypherpunks.su/tai64n/v3"
+	"go.cypherpunks.su/tai64n/v4"
 	"golang.org/x/net/netutil"
 	"lukechampine.com/blake3"
 )
@@ -92,9 +92,9 @@ 		log.Println(r.RemoteAddr, "non file form field")
 		return
 	}
 	t := time.Now()
-	ts := new(tai64n.TAI64N)
+	var ts tai64n.TAI64N
 	ts.FromTime(t)
-	tai := tai64n.Encode(ts[:])[1:]
+	tai := ts.Encode()[1:]
 	fnOrig := p.FileName()
 	fd, err := os.OpenFile(tai+".part", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
 	if err != nil {