diff --git a/conn.go b/conn.go
index bd8471d..eb43b00 100644
--- a/conn.go
+++ b/conn.go
@@ -86,7 +86,7 @@ func (c *Conn) EntryErr(pri Priority, msg string, attrs []Attr) error {
 	a = append(a, c.Common...)
 	a = append(a, attrs...)
 	err := c.WriteAttrs(a)
-	slices.Delete(a, 0, len(a)) // ensure GC doesn't see refs to old data
+	a = slices.Delete(a, 0, len(a)) // ensure GC doesn't see refs to old data
 	c.atts.Put(a)
 	return err
 }
@@ -97,7 +97,7 @@ func (c *Conn) WriteAttrs(attrs []Attr) error {
 	buf := c.bufs.Get().(*net.Buffers)
 	*buf = (*buf)[:0]
 	err := WireWrite(buf, c.s, attrs)
-	slices.Delete(*buf, 0, len(*buf)) // ensure GC doesn't see refs to old data
+	*buf = slices.Delete(*buf, 0, len(*buf)) // ensure GC doesn't see refs to old data
 	c.bufs.Put(buf)
 	return err
 }
diff --git a/conn_test.go b/conn_test.go
index 34bdffa..6c89a6a 100644
--- a/conn_test.go
+++ b/conn_test.go
@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"encoding/binary"
 	"encoding/hex"
+	"errors"
+	"fmt"
 	"io"
 	"net"
 	"path/filepath"
@@ -106,6 +108,10 @@ func checkWellFormedProto(buf []byte) (ok bool, pos int, desc string) {
 // Conn.
 func TestConcurrentEntries(t *testing.T) {
 	c := testConnector(t)
+	const (
+		numGoroutines = 16
+		numEntries    = 100
+	)
 
 	// attributes which will be common to all EntryErr calls
 	attr := make([]Attr, 0, 10 /* enough capacity to avoid realloc on append; might trigger data races */)
@@ -118,20 +124,35 @@ func TestConcurrentEntries(t *testing.T) {
 
 	// spawn goroutines
 	start := make(chan struct{})
-	for i := 0; i < 16; i++ {
+	result := make(chan error, numGoroutines)
+	for i := range numGoroutines {
 		go func() {
+			var err error
 			<-start
-			for j := 0; j < 100; j++ {
-				err := c.EntryErr(PriDebug, "message "+strconv.Itoa(i)+"."+strconv.Itoa(j), attr)
+			for j := range numEntries {
+				err = c.EntryErr(PriDebug, "message "+strconv.Itoa(i)+"."+strconv.Itoa(j), attr)
 				if err != nil {
-					t.Fatalf("message %d.%d error: %v", i, j, err)
+					err = fmt.Errorf("message %d.%d error: %w", i, j, err)
+					break
 				}
 			}
+			result <- err
 		}()
 	}
 
 	// try to get all the goroutines to start at roughly the same time
 	close(start)
+
+	// collect results
+	var errs []error
+	for range numGoroutines {
+		if err := <-result; err != nil {
+			errs = append(errs, err)
+		}
+	}
+	if err := errors.Join(errs...); err != nil {
+		t.Fatal(err)
+	}
 }
 
 // BenchmarkEntry is a benchmark for the common Entry function.
diff --git a/go.mod b/go.mod
index a721442..1124a22 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module src.lwithers.me.uk/go/journal
 
-go 1.22.0
+go 1.25