diff --git a/proto/common/v1.proto b/proto/common/v1.proto
index 0418b53..640a8d2 100644
--- a/proto/common/v1.proto
+++ b/proto/common/v1.proto
@@ -7,10 +7,10 @@ import "versionId/v1.proto";
 
 message Common_1 {
   // 32-byte random generated number
-  optional bytes docId = 1 [(required) = true];
+  bytes docId = 1 [(required) = true];
   repeated VersionId_1 links = 2;
-  optional google.protobuf.Timestamp createdAt = 3 [(required) = true];
-  optional google.protobuf.Timestamp updatedAt = 4 [(required) = true];
+  google.protobuf.Timestamp createdAt = 3 [(required) = true];
+  google.protobuf.Timestamp updatedAt = 4 [(required) = true];
   VersionId_1 originalVersionId = 5;
   bool deleted = 6 [(required) = true];
 }
diff --git a/proto/coreOwnership/v1.proto b/proto/coreOwnership/v1.proto
index 814fc68..4a78354 100644
--- a/proto/coreOwnership/v1.proto
+++ b/proto/coreOwnership/v1.proto
@@ -13,11 +13,11 @@ message CoreOwnership_1 {
 
   Common_1 common = 1;
 
-  optional bytes authCoreId = 5 [(required) = true];
-  optional bytes configCoreId = 6 [(required) = true];
-  optional bytes dataCoreId = 7 [(required) = true];
-  optional bytes blobCoreId = 8 [(required) = true];
-  optional bytes blobIndexCoreId = 9 [(required) = true];
+  bytes authCoreId = 5 [(required) = true];
+  bytes configCoreId = 6 [(required) = true];
+  bytes dataCoreId = 7 [(required) = true];
+  bytes blobCoreId = 8 [(required) = true];
+  bytes blobIndexCoreId = 9 [(required) = true];
   CoreSignatures coreSignatures = 10 [(required) = true];
   bytes identitySignature = 11;
 
diff --git a/proto/deviceInfo/v1.proto b/proto/deviceInfo/v1.proto
index 0d813f8..196764d 100644
--- a/proto/deviceInfo/v1.proto
+++ b/proto/deviceInfo/v1.proto
@@ -21,6 +21,6 @@ message DeviceInfo_1 {
     selfHostedServer = 4;
   }
 
-  optional string name = 5 [(required) = true];
+  string name = 5 [(required) = true];
   optional DeviceType deviceType = 6;
 }
diff --git a/proto/field/v1.proto b/proto/field/v1.proto
index 3d0d333..74d150b 100644
--- a/proto/field/v1.proto
+++ b/proto/field/v1.proto
@@ -14,7 +14,7 @@ message Field_1 {
 
   Common_1 common = 1;
 
-  optional string tagKey = 5 [(required) = true];
+  string tagKey = 5 [(required) = true];
   enum Type {
     type_unspecified = 0;
     text = 1;
@@ -22,7 +22,7 @@ message Field_1 {
     selectOne = 3;
     selectMultiple = 4;
   }
-  optional Type type = 6 [(required) = true];
+  Type type = 6 [(required) = true];
   optional string label = 7 [(required) = true];
   enum Appearance {
     appearance_unspecified = 0;
diff --git a/proto/icon/v1.proto b/proto/icon/v1.proto
index 6c6f82a..d7ae3e8 100644
--- a/proto/icon/v1.proto
+++ b/proto/icon/v1.proto
@@ -22,7 +22,7 @@ message Icon_1 {
       x3 = 3;
     }
 
-    optional PixelDensity pixelDensity = 1 [(required) = true];
+    PixelDensity pixelDensity = 1 [(required) = true];
   }
 
   message IconVariant {
@@ -43,8 +43,8 @@ message Icon_1 {
       int32 index = 2;
     }
 
-    optional Size size = 3 [(required) = true];
-    optional BlobVersionId blobVersionId = 4 [(required) = true];
+    Size size = 3 [(required) = true];
+    BlobVersionId blobVersionId = 4 [(required) = true];
   }
   repeated IconVariant variants = 3;
 }
diff --git a/proto/preset/v1.proto b/proto/preset/v1.proto
index 949dbb5..85f3d50 100644
--- a/proto/preset/v1.proto
+++ b/proto/preset/v1.proto
@@ -15,7 +15,7 @@ message Preset_1 {
 
   Common_1 common = 1;
 
-  optional string name = 5 [(required) = true];
+  string name = 5 [(required) = true];
   repeated Geometry geometry = 6;
   map<string, TagValue_1> tags = 7;
   map<string, TagValue_1> addTags = 8;
@@ -23,7 +23,7 @@ message Preset_1 {
   repeated FieldRef fieldRefs = 10;
   optional IconRef iconRef = 11;
   repeated string terms = 12;
-  optional string color = 13 [(required) = true];
+  string color = 13 [(required) = true];
 
   enum Geometry {
     geometry_unspecified = 0;
diff --git a/proto/role/v1.proto b/proto/role/v1.proto
index 68e89d9..440013b 100644
--- a/proto/role/v1.proto
+++ b/proto/role/v1.proto
@@ -13,6 +13,6 @@ message Role_1 {
 
   Common_1 common = 1;
 
-  optional bytes roleId = 5 [(required) = true];
+  bytes roleId = 5 [(required) = true];
   optional uint32 fromIndex = 6 [(required) = true];
 }
diff --git a/proto/translation/v1.proto b/proto/translation/v1.proto
index 7813b29..3bbe5c4 100644
--- a/proto/translation/v1.proto
+++ b/proto/translation/v1.proto
@@ -13,10 +13,10 @@ message Translation_1 {
   Common_1 common = 1;
   DocRef docRef = 2;
 
-  optional string propertyRef = 3 [(required) = true];
-  optional string languageCode = 4 [(required) = true];
-  optional string regionCode = 5 [(required) = true];
-  optional string message = 6 [(required) = true];
+  string propertyRef = 3 [(required) = true];
+  string languageCode = 4 [(required) = true];
+  string regionCode = 5 [(required) = true];
+  string message = 6 [(required) = true];
 
   message DocRef {
     bytes docId = 1;
diff --git a/src/lib/decode-conversions.ts b/src/lib/decode-conversions.ts
index 3bb02f5..af0376e 100644
--- a/src/lib/decode-conversions.ts
+++ b/src/lib/decode-conversions.ts
@@ -121,7 +121,7 @@ export const convertField: ConvertFunction<'field'> = (message, versionObj) => {
   const { common, schemaVersion, tagKey, type, label, ...rest } = message
   const jsonSchemaCommon = convertCommon(common, versionObj)
   ensure(tagKey, 'field', 'tagKey')
-  ensure(type, 'field', 'type')
+  ensure(type !== 'type_unspecified', 'field', 'type')
   return {
     ...jsonSchemaCommon,
     ...rest,
@@ -196,7 +196,7 @@ export const convertPreset: ConvertFunction<'preset'> = (
 
 export const convertRole: ConvertFunction<'role'> = (message, versionObj) => {
   const { common, schemaVersion, fromIndex, roleId, ...rest } = message
-  ensure(roleId?.length, 'role', 'roleId')
+  ensure(roleId.length, 'role', 'roleId')
   ensure(typeof fromIndex === 'number', 'role', 'fromIndex')
   const jsonSchemaCommon = convertCommon(common, versionObj)
   return {
@@ -237,11 +237,11 @@ export const convertCoreOwnership: ConvertFunction<'coreOwnership'> = (
     ...rest
   } = message
   ensure(coreSignatures, 'coreOwnership', 'coreSignatures')
-  ensure(authCoreId?.byteLength, 'coreOwnership', 'authCoreId')
-  ensure(configCoreId?.byteLength, 'coreOwnership', 'configCoreId')
-  ensure(dataCoreId?.byteLength, 'coreOwnership', 'dataCoreId')
-  ensure(blobCoreId?.byteLength, 'coreOwnership', 'blobCoreId')
-  ensure(blobIndexCoreId?.byteLength, 'coreOwnership', 'blobIndexCoreId')
+  ensure(authCoreId.byteLength, 'coreOwnership', 'authCoreId')
+  ensure(configCoreId.byteLength, 'coreOwnership', 'configCoreId')
+  ensure(dataCoreId.byteLength, 'coreOwnership', 'dataCoreId')
+  ensure(blobCoreId.byteLength, 'coreOwnership', 'blobCoreId')
+  ensure(blobIndexCoreId.byteLength, 'coreOwnership', 'blobIndexCoreId')
   const jsonSchemaCommon = convertCommon(common, versionObj)
   return {
     ...jsonSchemaCommon,
@@ -328,7 +328,11 @@ function convertIconVariant(
 ): Icon['variants'][number] {
   if (variant.variant?.$case === 'pngIcon') {
     const { pixelDensity } = variant.variant.pngIcon
-    ensure(pixelDensity, 'icon.variants[].pngIcon', 'pixelDensity')
+    ensure(
+      pixelDensity !== 'pixel_density_unspecified',
+      'icon.variants[].pngIcon',
+      'pixelDensity'
+    )
     return convertIconVariantPng({ ...variant, pixelDensity })
   } else if (variant.variant?.$case === 'svgIcon') {
     return convertIconVariantSvg(variant)
@@ -439,7 +443,12 @@ function convertCommon(
   common: ProtoTypesWithSchemaInfo['common'],
   versionObj: VersionIdObject
 ): Omit<MapeoCommon, 'schemaName'> {
-  if (!common || !common.docId || !common.createdAt || !common.updatedAt) {
+  if (
+    !common ||
+    !common.docId.byteLength ||
+    !common.createdAt ||
+    !common.updatedAt
+  ) {
     throw new Error('Missing required common properties')
   }