diff --git a/internal/ackhandler/sent_packet_handler_test.go b/internal/ackhandler/sent_packet_handler_test.go
index 21054d4a..4808ad51 100644
--- a/internal/ackhandler/sent_packet_handler_test.go
+++ b/internal/ackhandler/sent_packet_handler_test.go
@@ -1036,7 +1036,7 @@ var _ = Describe("SentPacketHandler", func() {
 					EncryptionLevel: protocol.Encryption0RTT,
 				}))
 			}
-			for i := protocol.PacketNumber(0); i < 6; i++ {
+			for i := protocol.PacketNumber(6); i < 12; i++ {
 				handler.SentPacket(ackElicitingPacket(&Packet{PacketNumber: i}))
 			}
 			Expect(handler.bytesInFlight).To(Equal(protocol.ByteCount(12)))
diff --git a/internal/ackhandler/sent_packet_history.go b/internal/ackhandler/sent_packet_history.go
index e8b9bd02..c5f52114 100644
--- a/internal/ackhandler/sent_packet_history.go
+++ b/internal/ackhandler/sent_packet_history.go
@@ -31,11 +31,12 @@ func (h *sentPacketHistory) GetPacket(p protocol.PacketNumber) *Packet {
 }
 
 // Iterate iterates through all packets.
-// The callback must not modify the history.
 func (h *sentPacketHistory) Iterate(cb func(*Packet) (cont bool, err error)) error {
 	cont := true
-	for el := h.packetList.Front(); cont && el != nil; el = el.Next() {
+	var next *PacketElement
+	for el := h.packetList.Front(); cont && el != nil; el = next {
 		var err error
+		next = el.Next()
 		cont, err = cb(&el.Value)
 		if err != nil {
 			return err
@@ -45,8 +46,6 @@ func (h *sentPacketHistory) Iterate(cb func(*Packet) (cont bool, err error)) err
 }
 
 // FirstOutStanding returns the first outstanding packet.
-// It must not be modified (e.g. retransmitted).
-// Use DequeueFirstPacketForRetransmission() to retransmit it.
 func (h *sentPacketHistory) FirstOutstanding() *Packet {
 	if !h.HasOutstandingPackets() {
 		return nil
diff --git a/internal/ackhandler/sent_packet_history_test.go b/internal/ackhandler/sent_packet_history_test.go
index c0e25d08..2506a58b 100644
--- a/internal/ackhandler/sent_packet_history_test.go
+++ b/internal/ackhandler/sent_packet_history_test.go
@@ -90,37 +90,47 @@ var _ = Describe("SentPacketHistory", func() {
 
 		It("iterates over all packets", func() {
 			var iterations []protocol.PacketNumber
-			err := hist.Iterate(func(p *Packet) (bool, error) {
+			Expect(hist.Iterate(func(p *Packet) (bool, error) {
 				iterations = append(iterations, p.PacketNumber)
 				return true, nil
-			})
-			Expect(err).ToNot(HaveOccurred())
+			})).To(Succeed())
 			Expect(iterations).To(Equal([]protocol.PacketNumber{10, 14, 18}))
 		})
 
 		It("stops iterating", func() {
 			var iterations []protocol.PacketNumber
-			err := hist.Iterate(func(p *Packet) (bool, error) {
+			Expect(hist.Iterate(func(p *Packet) (bool, error) {
 				iterations = append(iterations, p.PacketNumber)
 				return p.PacketNumber != 14, nil
-			})
-			Expect(err).ToNot(HaveOccurred())
+			})).To(Succeed())
 			Expect(iterations).To(Equal([]protocol.PacketNumber{10, 14}))
 		})
 
 		It("returns the error", func() {
 			testErr := errors.New("test error")
 			var iterations []protocol.PacketNumber
-			err := hist.Iterate(func(p *Packet) (bool, error) {
+			Expect(hist.Iterate(func(p *Packet) (bool, error) {
 				iterations = append(iterations, p.PacketNumber)
 				if p.PacketNumber == 14 {
 					return false, testErr
 				}
 				return true, nil
-			})
-			Expect(err).To(MatchError(testErr))
+			})).To(MatchError(testErr))
 			Expect(iterations).To(Equal([]protocol.PacketNumber{10, 14}))
 		})
+
+		It("allows deletions", func() {
+			var iterations []protocol.PacketNumber
+			Expect(hist.Iterate(func(p *Packet) (bool, error) {
+				iterations = append(iterations, p.PacketNumber)
+				if p.PacketNumber == 14 {
+					Expect(hist.Remove(14)).To(Succeed())
+				}
+				return true, nil
+			})).To(Succeed())
+			expectInHistory([]protocol.PacketNumber{10, 18})
+			Expect(iterations).To(Equal([]protocol.PacketNumber{10, 14, 18}))
+		})
 	})
 
 	Context("outstanding packets", func() {