diff --git a/internal/pkg/api/handleAck.go b/internal/pkg/api/handleAck.go
index 0e872c40f1..c0248ab9eb 100644
--- a/internal/pkg/api/handleAck.go
+++ b/internal/pkg/api/handleAck.go
@@ -620,6 +620,9 @@ func (ack *AckT) handleUpgrade(ctx context.Context, zlog zerolog.Logger, agent *
 			dl.FieldUpgradeStatus:    nil,
 			dl.FieldUpgradedAt:       now,
 		}
+		if agent.UpgradeDetails == nil {
+			doc[dl.FieldUpgradeAttempts] = nil
+		}
 	}
 
 	body, err := doc.Marshal()
diff --git a/internal/pkg/api/handleAck_test.go b/internal/pkg/api/handleAck_test.go
index 6c475bd41b..2b5bca4cd3 100644
--- a/internal/pkg/api/handleAck_test.go
+++ b/internal/pkg/api/handleAck_test.go
@@ -673,14 +673,26 @@ func TestAckHandleUpgrade(t *testing.T) {
 		name   string
 		event  UpgradeEvent
 		bulker func(t *testing.T) *ftesting.MockBulk
+		agent  *model.Agent
 	}{{
 		name:  "ok",
 		event: UpgradeEvent{},
 		bulker: func(t *testing.T) *ftesting.MockBulk {
 			m := ftesting.NewMockBulk()
-			m.On("Update", mock.Anything, mock.Anything, mock.Anything, mock.Anything, mock.Anything).Return(nil).Once()
+			m.On("Update", mock.Anything, mock.Anything, mock.Anything, mock.MatchedBy(func(p []byte) bool {
+				var body map[string]map[string]interface{}
+				if err := json.Unmarshal(p, &body); err != nil {
+					t.Fatal(err)
+				}
+				upgradeAttempts, ok := body["doc"]["upgrade_attempts"]
+				return ok == true && upgradeAttempts == nil
+			}), mock.Anything).Return(nil).Once()
 			return m
 		},
+		agent: &model.Agent{
+			ESDocument: model.ESDocument{Id: "ab12dcd8-bde0-4045-92dc-c4b27668d735"},
+			Agent:      &model.AgentMetadata{Version: "8.0.0"},
+		},
 	}, {
 		name: "retry signaled",
 		event: UpgradeEvent{
@@ -708,6 +720,10 @@ func TestAckHandleUpgrade(t *testing.T) {
 			}), mock.Anything).Return(nil).Once()
 			return m
 		},
+		agent: &model.Agent{
+			ESDocument: model.ESDocument{Id: "ab12dcd8-bde0-4045-92dc-c4b27668d735"},
+			Agent:      &model.AgentMetadata{Version: "8.0.0"},
+		},
 	}, {
 		name: "no more retries",
 		event: UpgradeEvent{
@@ -734,14 +750,34 @@ func TestAckHandleUpgrade(t *testing.T) {
 			}), mock.Anything).Return(nil).Once()
 			return m
 		},
+		agent: &model.Agent{
+			ESDocument: model.ESDocument{Id: "ab12dcd8-bde0-4045-92dc-c4b27668d735"},
+			Agent:      &model.AgentMetadata{Version: "8.0.0"},
+		},
+	}, {
+		name:  "keep upgrade_attempts if upgrade_details is not nil",
+		event: UpgradeEvent{},
+		bulker: func(t *testing.T) *ftesting.MockBulk {
+			m := ftesting.NewMockBulk()
+			m.On("Update", mock.Anything, mock.Anything, mock.Anything, mock.MatchedBy(func(p []byte) bool {
+				var body map[string]map[string]interface{}
+				if err := json.Unmarshal(p, &body); err != nil {
+					t.Fatal(err)
+				}
+				_, ok := body["doc"]["upgrade_attempts"]
+				return ok == false
+			}), mock.Anything).Return(nil).Once()
+			return m
+		},
+		agent: &model.Agent{
+			ESDocument:     model.ESDocument{Id: "ab12dcd8-bde0-4045-92dc-c4b27668d735"},
+			Agent:          &model.AgentMetadata{Version: "8.0.0"},
+			UpgradeDetails: &model.UpgradeDetails{},
+		},
 	}}
 	cfg := &config.Server{
 		Limits: config.ServerLimits{},
 	}
-	agent := &model.Agent{
-		ESDocument: model.ESDocument{Id: "ab12dcd8-bde0-4045-92dc-c4b27668d735"},
-		Agent:      &model.AgentMetadata{Version: "8.0.0"},
-	}
 	ctx := context.Background()
 	cache, err := cache.New(config.Cache{NumCounters: 100, MaxCost: 100000})
 	if err != nil {
@@ -753,7 +789,7 @@ func TestAckHandleUpgrade(t *testing.T) {
 			bulker := tc.bulker(t)
 			ack := NewAckT(cfg, bulker, cache)
 
-			err := ack.handleUpgrade(ctx, logger, agent, tc.event)
+			err := ack.handleUpgrade(ctx, logger, tc.agent, tc.event)
 			assert.NoError(t, err)
 			bulker.AssertExpectations(t)
 		})