diff --git a/acme/account_test.go b/acme/account_test.go
index 88718a9a..b8ce7276 100644
--- a/acme/account_test.go
+++ b/acme/account_test.go
@@ -135,7 +135,6 @@ func TestExternalAccountKey_BindTo(t *testing.T) {
 				if assert.True(t, errors.As(err, &ae)) {
 					assert.Equals(t, ae.Type, tt.err.Type)
 					assert.Equals(t, ae.Detail, tt.err.Detail)
-					assert.Equals(t, ae.Identifier, tt.err.Identifier)
 					assert.Equals(t, ae.Subproblems, tt.err.Subproblems)
 				}
 			} else {
diff --git a/acme/api/account_test.go b/acme/api/account_test.go
index 3f8641b8..d46c9eed 100644
--- a/acme/api/account_test.go
+++ b/acme/api/account_test.go
@@ -388,7 +388,6 @@ func TestHandler_GetOrdersByAccountID(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -828,7 +827,6 @@ func TestHandler_NewAccount(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1032,7 +1030,6 @@ func TestHandler_GetOrUpdateAccount(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
diff --git a/acme/api/eab_test.go b/acme/api/eab_test.go
index c923a2f6..14dbdad1 100644
--- a/acme/api/eab_test.go
+++ b/acme/api/eab_test.go
@@ -866,7 +866,6 @@ func TestHandler_validateExternalAccountBinding(t *testing.T) {
 					assert.Equals(t, ae.Status, tc.err.Status)
 					assert.HasPrefix(t, ae.Err.Error(), tc.err.Err.Error())
 					assert.Equals(t, ae.Detail, tc.err.Detail)
-					assert.Equals(t, ae.Identifier, tc.err.Identifier)
 					assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				}
 			} else {
@@ -1145,7 +1144,6 @@ func Test_validateEABJWS(t *testing.T) {
 				assert.Equals(t, tc.err.Status, err.Status)
 				assert.HasPrefix(t, err.Err.Error(), tc.err.Err.Error())
 				assert.Equals(t, tc.err.Detail, err.Detail)
-				assert.Equals(t, tc.err.Identifier, err.Identifier)
 				assert.Equals(t, tc.err.Subproblems, err.Subproblems)
 			} else {
 				assert.Nil(t, err)
diff --git a/acme/api/handler_test.go b/acme/api/handler_test.go
index e814aaba..7ef7cd68 100644
--- a/acme/api/handler_test.go
+++ b/acme/api/handler_test.go
@@ -193,7 +193,6 @@ func TestHandler_GetDirectory(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -366,7 +365,6 @@ func TestHandler_GetAuthorization(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -509,7 +507,6 @@ func TestHandler_GetCertificate(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.HasPrefix(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -768,7 +765,6 @@ func TestHandler_GetChallenge(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
diff --git a/acme/api/middleware_test.go b/acme/api/middleware_test.go
index faff0616..3db3773c 100644
--- a/acme/api/middleware_test.go
+++ b/acme/api/middleware_test.go
@@ -93,7 +93,6 @@ func TestHandler_addNonce(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -147,7 +146,6 @@ func TestHandler_addDirLink(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -252,7 +250,6 @@ func TestHandler_verifyContentType(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -320,7 +317,6 @@ func TestHandler_isPostAsGet(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -410,7 +406,6 @@ func TestHandler_parseJWS(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -606,7 +601,6 @@ func TestHandler_verifyAndExtractJWSPayload(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -808,7 +802,6 @@ func TestHandler_lookupJWK(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1008,7 +1001,6 @@ func TestHandler_extractJWK(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1384,7 +1376,6 @@ func TestHandler_validateJWS(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1567,7 +1558,6 @@ func TestHandler_extractOrLookupJWK(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1652,7 +1642,6 @@ func TestHandler_checkPrerequisites(t *testing.T) {
 				assert.FatalError(t, json.Unmarshal(bytes.TrimSpace(body), &ae))
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
diff --git a/acme/api/order_test.go b/acme/api/order_test.go
index b7b58b7f..9f03c547 100644
--- a/acme/api/order_test.go
+++ b/acme/api/order_test.go
@@ -486,7 +486,6 @@ func TestHandler_GetOrder(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1846,7 +1845,6 @@ func TestHandler_NewOrder(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -2144,7 +2142,6 @@ func TestHandler_FinalizeOrder(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
diff --git a/acme/api/revoke_test.go b/acme/api/revoke_test.go
index 240ac748..c4182400 100644
--- a/acme/api/revoke_test.go
+++ b/acme/api/revoke_test.go
@@ -1090,7 +1090,6 @@ func TestHandler_RevokeCert(t *testing.T) {
 
 				assert.Equals(t, ae.Type, tc.err.Type)
 				assert.Equals(t, ae.Detail, tc.err.Detail)
-				assert.Equals(t, ae.Identifier, tc.err.Identifier)
 				assert.Equals(t, ae.Subproblems, tc.err.Subproblems)
 				assert.Equals(t, res.Header["Content-Type"], []string{"application/problem+json"})
 			} else {
@@ -1230,7 +1229,6 @@ func TestHandler_isAccountAuthorized(t *testing.T) {
 			assert.Equals(t, acmeErr.Type, tc.err.Type)
 			assert.Equals(t, acmeErr.Status, tc.err.Status)
 			assert.Equals(t, acmeErr.Detail, tc.err.Detail)
-			assert.Equals(t, acmeErr.Identifier, tc.err.Identifier)
 			assert.Equals(t, acmeErr.Subproblems, tc.err.Subproblems)
 
 		})
@@ -1323,7 +1321,6 @@ func Test_wrapUnauthorizedError(t *testing.T) {
 			assert.Equals(t, acmeErr.Type, tc.want.Type)
 			assert.Equals(t, acmeErr.Status, tc.want.Status)
 			assert.Equals(t, acmeErr.Detail, tc.want.Detail)
-			assert.Equals(t, acmeErr.Identifier, tc.want.Identifier)
 			assert.Equals(t, acmeErr.Subproblems, tc.want.Subproblems)
 		})
 	}
diff --git a/acme/errors.go b/acme/errors.go
index 95053908..44f367a0 100644
--- a/acme/errors.go
+++ b/acme/errors.go
@@ -275,14 +275,8 @@ type Error struct {
 	Type        string       `json:"type"`
 	Detail      string       `json:"detail"`
 	Subproblems []Subproblem `json:"subproblems,omitempty"`
-
-	// 	The "identifier" field MUST NOT be present at the top level in ACME
-	//    problem documents.  It can only be present in subproblems.
-	//    Subproblems need not all have the same type, and they do not need to
-	//    match the top level type.
-	Identifier Identifier `json:"identifier,omitempty"` // TODO(hs): seems unused and MUST NOT be present; this can likely be removed
-	Err        error      `json:"-"`
-	Status     int        `json:"-"`
+	Err         error        `json:"-"`
+	Status      int          `json:"-"`
 }
 
 // Subproblem represents an ACME subproblem. It's fairly
@@ -290,8 +284,12 @@ type Error struct {
 // include subproblems itself, the error is reflected
 // in the Detail property and doesn't have a Status.
 type Subproblem struct {
-	Type       string      `json:"type"`
-	Detail     string      `json:"detail"`
+	Type   string `json:"type"`
+	Detail string `json:"detail"`
+	// The "identifier" field MUST NOT be present at the top level in ACME
+	// problem documents.  It can only be present in subproblems.
+	// Subproblems need not all have the same type, and they do not need to
+	// match the top level type.
 	Identifier *Identifier `json:"identifier,omitempty"`
 }