diff --git a/pkg/modules/chromium/routes_test.go b/pkg/modules/chromium/routes_test.go
index d215730d..456ed8d3 100644
--- a/pkg/modules/chromium/routes_test.go
+++ b/pkg/modules/chromium/routes_test.go
@@ -734,7 +734,7 @@ func TestConvertUrl(t *testing.T) {
 			engine: &gotenberg.PdfEngineMock{ConvertMock: func(ctx context.Context, logger *zap.Logger, formats gotenberg.PdfFormats, inputPath, outputPath string) error {
 				return nil
 			}},
-			pdfFormats:             gotenberg.PdfFormats{PdfA: gotenberg.PdfA1a},
+			pdfFormats:             gotenberg.PdfFormats{PdfA: gotenberg.PdfA1b},
 			options:                DefaultOptions(),
 			expectError:            false,
 			expectHttpError:        false,
diff --git a/pkg/modules/libreoffice/api/api.go b/pkg/modules/libreoffice/api/api.go
index b5ac69d1..288ef10a 100644
--- a/pkg/modules/libreoffice/api/api.go
+++ b/pkg/modules/libreoffice/api/api.go
@@ -51,7 +51,7 @@ type Options struct {
 	// Optional.
 	PageRanges string
 
-	// PdfFormats allows to convert the resulting PDF to PDF/A-1a, PDF/A-2b,
+	// PdfFormats allows to convert the resulting PDF to PDF/A-1b, PDF/A-2b,
 	// PDF/A-3b and PDF/UA.
 	// Optional.
 	PdfFormats gotenberg.PdfFormats
diff --git a/pkg/modules/libreoffice/api/libreoffice.go b/pkg/modules/libreoffice/api/libreoffice.go
index 8ceaa416..28e56aef 100644
--- a/pkg/modules/libreoffice/api/libreoffice.go
+++ b/pkg/modules/libreoffice/api/libreoffice.go
@@ -275,7 +275,7 @@ func (p *libreOfficeProcess) pdf(ctx context.Context, logger *zap.Logger, inputP
 
 	switch options.PdfFormats.PdfA {
 	case "":
-	case gotenberg.PdfA1a:
+	case gotenberg.PdfA1b:
 		args = append(args, "--export", "SelectPdfVersion=1")
 	case gotenberg.PdfA2b:
 		args = append(args, "--export", "SelectPdfVersion=2")
diff --git a/pkg/modules/libreoffice/api/libreoffice_test.go b/pkg/modules/libreoffice/api/libreoffice_test.go
index b69ac414..85bf6053 100644
--- a/pkg/modules/libreoffice/api/libreoffice_test.go
+++ b/pkg/modules/libreoffice/api/libreoffice_test.go
@@ -394,7 +394,7 @@ func TestLibreOfficeProcess_pdf(t *testing.T) {
 			expectError:  false,
 		},
 		{
-			scenario: "success (PDF/A-1a)",
+			scenario: "success (PDF/A-1b)",
 			libreOffice: newLibreOfficeProcess(
 				libreOfficeArguments{
 					binPath:      os.Getenv("LIBREOFFICE_BIN_PATH"),
@@ -417,7 +417,7 @@ func TestLibreOfficeProcess_pdf(t *testing.T) {
 
 				return fs
 			}(),
-			options:      Options{PdfFormats: gotenberg.PdfFormats{PdfA: gotenberg.PdfA1a}},
+			options:      Options{PdfFormats: gotenberg.PdfFormats{PdfA: gotenberg.PdfA1b}},
 			cancelledCtx: false,
 			start:        true,
 			expectError:  false,
diff --git a/pkg/modules/libreoffice/pdfengine/pdfengine.go b/pkg/modules/libreoffice/pdfengine/pdfengine.go
index 9c41d4aa..9029e8f7 100644
--- a/pkg/modules/libreoffice/pdfengine/pdfengine.go
+++ b/pkg/modules/libreoffice/pdfengine/pdfengine.go
@@ -52,7 +52,7 @@ func (engine *LibreOfficePdfEngine) Merge(ctx context.Context, logger *zap.Logge
 }
 
 // Convert converts the given PDF to a specific PDF format. Currently, only the
-// PDF/A-1a, PDF/A-2b, PDF/A-3b and PDF/UA formats are available. If another
+// PDF/A-1b, PDF/A-2b, PDF/A-3b and PDF/UA formats are available. If another
 // PDF format is requested, it returns a [gotenberg.ErrPdfFormatNotSupported]
 // error.
 func (engine *LibreOfficePdfEngine) Convert(ctx context.Context, logger *zap.Logger, formats gotenberg.PdfFormats, inputPath, outputPath string) error {
diff --git a/pkg/modules/libreoffice/routes_test.go b/pkg/modules/libreoffice/routes_test.go
index b3d42b43..751333c0 100644
--- a/pkg/modules/libreoffice/routes_test.go
+++ b/pkg/modules/libreoffice/routes_test.go
@@ -88,9 +88,12 @@ func TestConvertRoute(t *testing.T) {
 					"document.docx": "/document.docx",
 				})
 				ctx.SetValues(map[string][]string{
-					"pdfFormat": {
+					"pdfa": {
 						"foo",
 					},
+					"nativePdfFormats": {
+						"false",
+					},
 				})
 				return ctx
 			}(),
@@ -120,8 +123,11 @@ func TestConvertRoute(t *testing.T) {
 					"document.docx": "/document.docx",
 				})
 				ctx.SetValues(map[string][]string{
-					"pdfFormat": {
-						gotenberg.PdfA1a,
+					"pdfa": {
+						gotenberg.PdfA1b,
+					},
+					"nativePdfFormats": {
+						"false",
 					},
 				})
 				return ctx
@@ -209,7 +215,7 @@ func TestConvertRoute(t *testing.T) {
 			expectOutputPathsCount: 2,
 		},
 		{
-			scenario: "success with non-native PDF/A (single file)",
+			scenario: "success with non-native PDF/A & PDF/UA (single file)",
 			ctx: func() *api.ContextMock {
 				ctx := &api.ContextMock{Context: new(api.Context)}
 				ctx.SetFiles(map[string]string{
@@ -217,7 +223,10 @@ func TestConvertRoute(t *testing.T) {
 				})
 				ctx.SetValues(map[string][]string{
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
+					},
+					"pdfua": {
+						"true",
 					},
 					"nativePdfFormats": {
 						"false",
@@ -254,13 +263,13 @@ func TestConvertRoute(t *testing.T) {
 						"true",
 					},
 					"pdfFormat": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"nativePdfFormat": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"pdfua": {
 						"true",
@@ -375,7 +384,7 @@ func TestConvertRoute(t *testing.T) {
 						"true",
 					},
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"nativePdfFormats": {
 						"false",
@@ -469,7 +478,7 @@ func TestConvertRoute(t *testing.T) {
 			expectOutputPathsCount: 1,
 		},
 		{
-			scenario: "success with non-native PDF/A (merge)",
+			scenario: "success with non-native PDF/A & PDF/UA (merge)",
 			ctx: func() *api.ContextMock {
 				ctx := &api.ContextMock{Context: new(api.Context)}
 				ctx.SetFiles(map[string]string{
@@ -481,7 +490,54 @@ func TestConvertRoute(t *testing.T) {
 						"true",
 					},
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
+					},
+					"pdfua": {
+						"true",
+					},
+					"nativePdfFormats": {
+						"false",
+					},
+				})
+				return ctx
+			}(),
+			libreOffice: &libreofficeapi.ApiMock{
+				PdfMock: func(ctx context.Context, logger *zap.Logger, inputPath, outputPath string, options libreofficeapi.Options) error {
+					return nil
+				},
+				ExtensionsMock: func() []string {
+					return []string{".docx"}
+				},
+			},
+			engine: &gotenberg.PdfEngineMock{
+				MergeMock: func(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
+					return nil
+				},
+				ConvertMock: func(ctx context.Context, logger *zap.Logger, formats gotenberg.PdfFormats, inputPath, outputPath string) error {
+					return nil
+				},
+			},
+			expectError:            false,
+			expectHttpError:        false,
+			expectOutputPathsCount: 1,
+		},
+		{
+			scenario: "success with non-native PDF/A & PDF/UA (merge)",
+			ctx: func() *api.ContextMock {
+				ctx := &api.ContextMock{Context: new(api.Context)}
+				ctx.SetFiles(map[string]string{
+					"document.docx":  "/document.docx",
+					"document2.docx": "/document2.docx",
+				})
+				ctx.SetValues(map[string][]string{
+					"merge": {
+						"true",
+					},
+					"pdfa": {
+						gotenberg.PdfA1b,
+					},
+					"pdfua": {
+						"true",
 					},
 					"nativePdfFormats": {
 						"false",
diff --git a/pkg/modules/pdfengines/routes_test.go b/pkg/modules/pdfengines/routes_test.go
index cf71be10..076c95d1 100644
--- a/pkg/modules/pdfengines/routes_test.go
+++ b/pkg/modules/pdfengines/routes_test.go
@@ -99,7 +99,7 @@ func TestMergeHandler(t *testing.T) {
 				})
 				ctx.SetValues(map[string][]string{
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 				})
 				return ctx
@@ -127,7 +127,7 @@ func TestMergeHandler(t *testing.T) {
 				})
 				ctx.SetValues(map[string][]string{
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 				})
 				return ctx
@@ -157,7 +157,7 @@ func TestMergeHandler(t *testing.T) {
 						gotenberg.PdfA1a,
 					},
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"pdfua": {
 						"true",
@@ -259,7 +259,7 @@ func TestConvertHandler(t *testing.T) {
 				})
 				ctx.SetValues(map[string][]string{
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 				})
 				return ctx
@@ -283,7 +283,7 @@ func TestConvertHandler(t *testing.T) {
 				})
 				ctx.SetValues(map[string][]string{
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 				})
 				return ctx
@@ -306,7 +306,7 @@ func TestConvertHandler(t *testing.T) {
 				})
 				ctx.SetValues(map[string][]string{
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 				})
 				ctx.SetCancelled(true)
@@ -333,7 +333,7 @@ func TestConvertHandler(t *testing.T) {
 						gotenberg.PdfA1a,
 					},
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"pdfua": {
 						"true",
@@ -363,7 +363,7 @@ func TestConvertHandler(t *testing.T) {
 						gotenberg.PdfA1a,
 					},
 					"pdfa": {
-						gotenberg.PdfA1a,
+						gotenberg.PdfA1b,
 					},
 					"pdfua": {
 						"true",