diff --git a/openrtb-core/src/main/protobuf/openrtb.proto b/openrtb-core/src/main/protobuf/openrtb.proto
index f2d57ec6..475750f1 100644
--- a/openrtb-core/src/main/protobuf/openrtb.proto
+++ b/openrtb-core/src/main/protobuf/openrtb.proto
@@ -1,7 +1,7 @@
 option java_outer_classname = "OpenRtb";
 package com.google.openrtb;
 
-// Copyright 2021 Google Inc. All Rights Reserved.
+// Copyright 2022 Google Inc. All Rights Reserved.
 
 // OpenRTB extensions ("ext" fields in the spec & JSON representation)
 // are represented here by Protocol Buffer extensions. This proto only
@@ -72,7 +72,7 @@ message BidRequest {
   // Flag to indicate if Exchange can verify that the impressions offered
   // represent all of the impressions available in context (e.g., all on the
   // web page, all video spots such as pre/mid/post roll) to support
-  // road-blocking. 0 = no or unknown, 1 = yes, the impressions offered
+  // road-blocking. false = no or unknown, true = yes, the impressions offered
   // represent all that are available.
   optional bool allimps = 10 [default = false];
 
@@ -94,7 +94,7 @@ message BidRequest {
   repeated string bapp = 16;
 
   // Indicator of test mode in which auctions are not billable,
-  // where 0 = live mode, 1 = test mode.
+  // where false = live mode, true = test mode.
   optional bool test = 15 [default = false];
 
   // Block list of buyer seats (e.g., advertisers, agencies) restricted
@@ -128,7 +128,7 @@ message BidRequest {
   // demand in decisioning.
   message Source {
     // Entity responsible for the final impression sale decision,
-    // where 0 = exchange, 1 = upstream source
+    // where false = exchange, true = upstream source
     // RECOMMENDED by the OpenRTB specification.
     optional bool fd = 1;
 
@@ -185,7 +185,7 @@ message BidRequest {
     // to customize ad code by partner. Recommended for video and/or apps.
     optional string displaymanagerver = 5;
 
-    // 1 = the ad is interstitial or full screen, 0 = not interstitial.
+    // true = the ad is interstitial or full screen, false = not interstitial.
     optional bool instl = 6;
 
     // Identifier for specific ad placement or ad tag that was used to
@@ -201,14 +201,14 @@ message BidRequest {
     optional string bidfloorcur = 9 [default = "USD"];
 
     // Indicates the type of browser opened upon clicking the
-    // creative in an app, where 0 = embedded, 1 = native.
+    // creative in an app, where false = embedded, true = native.
     // Note that the Safari View Controller in iOS 9.x devices is considered
     // a native browser for purposes of this attribute.
     optional bool clickbrowser = 16;
 
     // Flag to indicate if the impression requires secure HTTPS URL creative
-    // assets and markup, where 0 = non-secure, 1 = secure.  If omitted,
-    // the secure state is unknown, but non-secure HTTP support can be assumed.
+    // assets and markup.  If omitted, the secure state is unknown, but
+    // non-secure HTTP support can be assumed.
     optional bool secure = 12;
 
     // Array of exchange-specific names of supported iframe busters.
@@ -285,26 +285,34 @@ message BidRequest {
       // requirement. Otherwise it is a preferred height.
       optional int32 h = 2;
 
-      // Array of format objects representing the banner sizes permitted.
-      // If none are specified, then use of the h and w attributes
-      // is highly recommended.
-      repeated Format format = 15;
+      // OpenRTB 2.4: This object represents an allowed size (i.e.,
+      // height and width combination) for a banner impression.
+      // These are typically used in an array for an impression where
+      // multiple sizes are permitted.
+      message Format {
+        // Width in device independent pixels (DIPS).
+        optional int32 w = 1;
 
-      // NOTE: Deprecated in favor of the format array.
-      // Maximum width in device independent pixels (DIPS).
-      optional int32 wmax = 11 [deprecated = true];
+        // Height in device independent pixels (DIPS).
+        optional int32 h = 2;
 
-      // NOTE: Deprecated in favor of the format array.
-      // Maximum height in device independent pixels (DIPS).
-      optional int32 hmax = 12 [deprecated = true];
+        // Relative width when expressing size as a ratio.
+        optional int32 wratio = 3;
 
-      // NOTE: Deprecated in favor of the format array.
-      // Minimum width in device independent pixels (DIPS).
-      optional int32 wmin = 13 [deprecated = true];
+        // Relative height when expressing size as a ratio.
+        optional int32 hratio = 4;
 
-      // NOTE: Deprecated in favor of the format array.
-      // Minimum height in device independent pixels (DIPS).
-      optional int32 hmin = 14 [deprecated = true];
+        // The minimum width in device independent pixels (DIPS) at
+        // which the ad will be displayed when the size is expressed as a ratio.
+        optional int32 wmin = 5;
+
+        // Extensions.
+        extensions 100 to 9999;
+      }
+      // Array of format objects representing the banner sizes permitted.
+      // If none are specified, then use of the h and w attributes
+      // is highly recommended.
+      repeated Format format = 15;
 
       // Unique identifier for this banner object. Recommended when Banner
       // objects are used with a Video object (Section 3.2.4) to represent
@@ -340,36 +348,27 @@ message BidRequest {
       // Relevant only for Banner objects used with a Video object
       // (Section 3.2.7) in an array of companion ads. Indicates the
       // companion banner rendering mode relative to the associated
-      // video, where 0 = concurrent, 1 = end-card.
+      // video, where false = concurrent, true = end-card.
       optional bool vcm = 16;
 
-      // Extensions.
-      extensions 100 to 9999;
-
-      // OpenRTB 2.4: This object represents an allowed size (i.e.,
-      // height and width combination) for a banner impression.
-      // These are typically used in an array for an impression where
-      // multiple sizes are permitted.
-      message Format {
-        // Width in device independent pixels (DIPS).
-        optional int32 w = 1;
-
-        // Height in device independent pixels (DIPS).
-        optional int32 h = 2;
+      // DEPRECATED in OpenRTB 2.4+. Prefer the field <code>format</code>.
+      // Maximum width in device independent pixels (DIPS).
+      optional int32 wmax = 11 [deprecated = true];
 
-        // Relative width when expressing size as a ratio.
-        optional int32 wratio = 3;
+      // DEPRECATED in OpenRTB 2.4+. Prefer the field <code>format</code>.
+      // Maximum height in device independent pixels (DIPS).
+      optional int32 hmax = 12 [deprecated = true];
 
-        // Relative height when expressing size as a ratio.
-        optional int32 hratio = 4;
+      // DEPRECATED in OpenRTB 2.4+. Prefer the field <code>format</code>.
+      // Minimum width in device independent pixels (DIPS).
+      optional int32 wmin = 13 [deprecated = true];
 
-        // The minimum width in device independent pixels (DIPS) at
-        // which the ad will be displayed when the size is expressed as a ratio.
-        optional int32 wmin = 5;
+      // DEPRECATED in OpenRTB 2.4+. Prefer the field <code>format</code>.
+      // Minimum height in device independent pixels (DIPS).
+      optional int32 hmin = 14 [deprecated = true];
 
-        // Extensions.
-        extensions 100 to 9999;
-      }
+      // Extensions.
+      extensions 100 to 9999;
     }
 
     // OpenRTB 2.0: This object represents an in-stream video impression.
@@ -393,20 +392,19 @@ message BidRequest {
       // REQUIRED by the OpenRTB specification: at least 1 element.
       repeated string mimes = 1;
 
-      // Indicates if the impression must be linear, nonlinear, etc.
-      // If none specified, assume all are allowed.
-      optional VideoLinearity linearity = 2;
-
       // Minimum video ad duration in seconds.
       // RECOMMENDED by the OpenRTB specification.
-      optional int32 minduration = 3;
+      optional int32 minduration = 3 [default = 0];
 
       // Maximum video ad duration in seconds.
       // RECOMMENDED by the OpenRTB specification.
       optional int32 maxduration = 4;
 
-      // Deprecated; use protocols.
-      optional Protocol protocol = 5 [deprecated = true];
+      // Indicates the start delay in seconds for pre-roll, mid-roll, or
+      // post-roll ad placements.
+      // Refer to enum StartDelay for generic values.
+      // RECOMMENDED by the OpenRTB specification.
+      optional int32 startdelay = 8;
 
       // Array of supported video bid response protocols.
       // At least one supported protocol must be specified.
@@ -420,14 +418,14 @@ message BidRequest {
       // RECOMMENDED by the OpenRTB specification.
       optional int32 h = 7;
 
-      // Indicates the start delay in seconds for pre-roll, mid-roll, or
-      // post-roll ad placements.
-      // Refer to enum StartDelay for generic values.
-      // RECOMMENDED by the OpenRTB specification.
-      optional int32 startdelay = 8;
+      // Placement type for the impression.
+      optional VideoPlacementType placement = 26;
 
-      // Indicates if the player will allow the video to be skipped,
-      // where 0 = no, 1 = yes.
+      // Indicates if the impression must be linear, nonlinear, etc.
+      // If none specified, assume all are allowed.
+      optional VideoLinearity linearity = 2;
+
+      // Indicates if the player will allow the video to be skipped.
       // If a bidder sends markup/creative that is itself skippable, the
       // Bid object should include the attr array with an element of
       // 16 indicating skippable video.
@@ -463,7 +461,7 @@ message BidRequest {
       optional int32 maxbitrate = 13;
 
       // Indicates if letter-boxing of 4:3 content into a 16:9 window is
-      // allowed, where 0 = no, 1 = yes.
+      // allowed.
       optional bool boxingallowed = 14 [default = true];
 
       // Playback methods that may be in use. If none are specified, any
@@ -473,6 +471,9 @@ message BidRequest {
       // the first element of this array in preparation for this change.
       repeated PlaybackMethod playbackmethod = 15 [packed = true];
 
+      // The event that causes playback to end.
+      optional PlaybackCessationMode playbackend = 27;
+
       // Supported delivery methods (e.g., streaming, progressive).
       // If none specified, assume all are supported.
       repeated ContentDeliveryMethod delivery = 16 [packed = true];
@@ -483,10 +484,6 @@ message BidRequest {
       // Array of Banner objects (Section 3.2.3) if companion ads are available.
       repeated Banner companionad = 18;
 
-      // Companion ads in OpenRTB 2.1 format. (Or to be precise, interpretations
-      // based on the buggy sample message in 5.1.4, fixed later in 2.2.)
-      optional CompanionAd companionad_21 = 22 [deprecated = true];
-
       // List of supported API frameworks for this impression.
       // If an API is not explicitly listed, it is assumed not to be supported.
       repeated APIFramework api = 19 [packed = true];
@@ -495,20 +492,20 @@ message BidRequest {
       // objects are included via the companionad array.
       repeated CompanionType companiontype = 20 [packed = true];
 
-      // Placement type for the impression.
-      optional VideoPlacementType placement = 26;
-
-      // The event that causes playback to end.
-      optional PlaybackCessationMode playbackend = 27;
-
-      // Extensions.
-      extensions 100 to 9999;
+      // DEPRECATED in OpenRTB 2.3+. Prefer the field <code>protocols</code>.
+      // Video bid response protocol.
+      optional Protocol protocol = 5 [deprecated = true];
 
       // OpenRTB 2.1 compatibility.
       message CompanionAd {
         repeated Banner banner = 1;
         extensions 100 to 9999;
       }
+      // REMOVED in OpenRTB 2.2+. Prefer the field <code>companionad</code>.
+      optional CompanionAd companionad_21 = 22 [deprecated = true];
+
+      // Extensions.
+      extensions 100 to 9999;
     }
 
     // This object represents an audio type impression. Many of the fields
@@ -531,7 +528,7 @@ message BidRequest {
 
       // Minimum audio ad duration in seconds.
       // RECOMMENDED by the OpenRTB specification.
-      optional int32 minduration = 2;
+      optional int32 minduration = 2 [default = 0];
 
       // Maximum audio ad duration in seconds.
       // RECOMMENDED by the OpenRTB specification.
@@ -590,7 +587,7 @@ message BidRequest {
       optional FeedType feed = 22;
 
       // Indicates if the ad is stitched with audio content or delivered
-      // independently, where 0 = no, 1 = yes.
+      // independently.
       optional bool stitched = 23;
 
       // Volume normalization mode.
@@ -654,8 +651,8 @@ message BidRequest {
     // Deal objects. Refer to Section 7.2 for more details.
     message Pmp {
       // Indicator of auction eligibility to seats named in the Direct Deals
-      // object, where 0 = all bids are accepted, 1 = bids are restricted to
-      // the deals specified and the terms thereof.
+      // object, where false = all bids are accepted, true = bids are restricted
+      // to the deals specified and the terms thereof.
       optional bool private_auction = 1 [default = false];
 
       // Array of Deal (Section 3.2.18) objects that convey the specific deals
@@ -737,7 +734,7 @@ message BidRequest {
     // URL of the page where the impression will be shown.
     optional string page = 7;
 
-    // Indicates if the site has a privacy policy, where 0 = no, 1 = yes.
+    // Indicates if the site has a privacy policy.
     optional bool privacypolicy = 8;
 
     // Referrer URL that caused navigation to the current page.
@@ -760,7 +757,7 @@ message BidRequest {
     optional string keywords = 13;
 
     // Indicates if the site has been programmed to optimize layout
-    // when viewed on mobile devices, where 0 = no, 1 = yes.
+    // when viewed on mobile devices.
     optional bool mobile = 15;
 
     // Extensions.
@@ -809,10 +806,10 @@ message BidRequest {
     // TVs), it can be provided by the publisher directly in the request.
     optional string bundle = 8;
 
-    // Indicates if the app has a privacy policy, where 0 = no, 1 = yes.
+    // Indicates if the app has a privacy policy.
     optional bool privacypolicy = 9;
 
-    // 0 = app is free, 1 = the app is a paid version.
+    // false = app is free, true = the app is a paid version.
     optional bool paid = 10;
 
     // Details about the Publisher (Section 3.2.8) of the app.
@@ -895,6 +892,9 @@ message BidRequest {
     // International Standard Recording Code conforming to ISO-3901.
     optional string isrc = 24;
 
+    // Details about the content Producer (Section 3.2.10).
+    optional Producer producer = 15;
+
     // URL of the content, for buy-side contextualization or review.
     optional string url = 6;
 
@@ -905,16 +905,8 @@ message BidRequest {
     // Production quality.
     optional ProductionQuality prodq = 25;
 
-    // NOTE: Deprecated in favor of prodq.
-    // Video quality per IAB's classification.
-    optional ProductionQuality videoquality = 8 [deprecated = true];
-
-    // Comma separated list of keywords describing the content.
-    // Note: OpenRTB 2.2 allowed an array-of-strings as alternate implementation
-    // but this was fixed in 2.3+ where it's definitely a single string with CSV
-    // content again. Compatibility with some OpenRTB 2.2 exchanges that adopted
-    // the alternate representation may require custom handling of the JSON.
-    optional string keywords = 9;
+    // Type of content (game, video, text, etc.).
+    optional ContentContext context = 20;
 
     // Content rating (e.g., MPAA).
     optional string contentrating = 10;
@@ -922,33 +914,41 @@ message BidRequest {
     // User rating of the content (e.g., number of stars, likes, etc.).
     optional string userrating = 11;
 
-    // Type of content (game, video, text, etc.).
-    optional ContentContext context = 20;
+    // Media rating per QAG guidelines.
+    optional QAGMediaRating qagmediarating = 17;
 
-    // OpenRTB <= 2.2 compatibility; use context for 2.3+.
-    optional string context_22 = 12;
+    // Comma separated list of keywords describing the content.
+    // Note: OpenRTB 2.2 allowed an array-of-strings as alternate implementation
+    // but this was fixed in 2.3+ where it's definitely a single string with CSV
+    // content again. Compatibility with some OpenRTB 2.2 exchanges that adopted
+    // the alternate representation may require custom handling of the JSON.
+    optional string keywords = 9;
 
-    // 0 = not live, 1 = content is live (e.g., stream, live blog).
+    // false = not live, true = content is live (e.g., stream, live blog).
     optional bool livestream = 13;
 
-    // 0 = indirect, 1 = direct.
+    // false = indirect, true = direct.
     optional bool sourcerelationship = 14;
 
-    // Details about the content Producer (Section 3.2.10).
-    optional Producer producer = 15;
-
     // Length of content in seconds; appropriate for video or audio.
     optional int32 len = 16;
 
-    // Media rating per QAG guidelines.
-    optional QAGMediaRating qagmediarating = 17;
+    // Content language using ISO-639-1-alpha-2.
+    optional string language = 19;
 
     // Indicator of whether or not the content is embeddable (e.g., an
-    // embeddable video player), where 0 = no, 1 = yes.
+    // embeddable video player).
     optional bool embeddable = 18;
 
-    // Content language using ISO-639-1-alpha-2.
-    optional string language = 19;
+    // Additional content data. Each object represents a different data source.
+    repeated Data data = 28;
+
+    // DEPRECATED in OpenRTB 2.4+. Prefer the field <code>prodq</code>.
+    // Video quality per IAB's classification.
+    optional ProductionQuality videoquality = 8 [deprecated = true];
+
+    // REMOVED in OpenRTB 2.3+. Prefer the field <code>context</code>.
+    optional string context_22 = 12 [deprecated = true];
 
     // Extensions.
     extensions 100 to 9999;
@@ -982,11 +982,22 @@ message BidRequest {
   // hardware, platform, location, and carrier data. The device can refer to a
   // mobile handset, a desktop computer, set top box, or other digital device.
   message Device {
+    // Location of the device assumed to be the user's current location defined
+    // by a Geo object (Section 3.2.12).
+    // RECOMMENDED by the OpenRTB specification.
+    optional Geo geo = 4;
+
     // Standard "Do Not Track" flag as set in the header by the browser,
-    // where 0 = tracking is unrestricted, 1 = do not track.
+    // where false = tracking is unrestricted, true = do not track.
     // RECOMMENDED by the OpenRTB specification.
     optional bool dnt = 1;
 
+    // "Limit Ad Tracking" signal commercially endorsed (e.g., iOS, Android),
+    // where false = tracking is unrestricted, true = tracking must be limited
+    // per commercial guidelines.
+    // RECOMMENDED by the OpenRTB specification.
+    optional bool lmt = 23;
+
     // Browser user agent string. Certain data may be redacted or replaced.
     // RECOMMENDED by the OpenRTB specification.
     optional string ua = 2;
@@ -995,32 +1006,11 @@ message BidRequest {
     // RECOMMENDED by the OpenRTB specification.
     optional string ip = 3;
 
-    // Location of the device assumed to be the user's current location defined
-    // by a Geo object (Section 3.2.12).
-    // RECOMMENDED by the OpenRTB specification.
-    optional Geo geo = 4;
-
-    // Hardware device ID (e.g., IMEI); hashed via SHA1.
-    optional string didsha1 = 5;
-
-    // Hardware device ID (e.g., IMEI); hashed via MD5.
-    optional string didmd5 = 6;
-
-    // Platform device ID (e.g., Android ID); hashed via SHA1.
-    optional string dpidsha1 = 7;
-
-    // Platform device ID (e.g., Android ID); hashed via MD5.
-    optional string dpidmd5 = 8;
-
     // IPv6 address closest to device.
     optional string ipv6 = 9;
 
-    // Carrier or ISP (e.g., "VERIZON") using exchange curated string
-    // names which should be published to bidders a priori.
-    optional string carrier = 10;
-
-    // Browser language using ISO-639-1-alpha-2.
-    optional string language = 11;
+    // The general type of device.
+    optional DeviceType devicetype = 18;
 
     // Device make (e.g., "Apple").
     optional string make = 12;
@@ -1049,36 +1039,22 @@ message BidRequest {
     // The ratio of physical pixels to device independent pixels.
     optional double pxratio = 28;
 
-    // Support for JavaScript, where 0 = no, 1 = yes.
+    // Support for JavaScript.
     optional bool js = 16;
 
     // Indicates if the geolocation API will be available to JavaScript
-    // code running in the banner, where 0 = no, 1 = yes.
+    // code running in the banner.
     optional bool geofetch = 29;
 
-    // Network connection type.
-    optional ConnectionType connectiontype = 17;
-
-    // The general type of device.
-    optional DeviceType devicetype = 18;
-
     // Version of Flash supported by the browser.
     optional string flashver = 19;
 
-    // ID sanctioned for advertiser use in the clear (i.e., not hashed).
-    optional string ifa = 20;
-
-    // MAC address of the device; hashed via SHA1.
-    optional string macsha1 = 21;
-
-    // MAC address of the device; hashed via MD5.
-    optional string macmd5 = 22;
+    // Browser language using ISO-639-1-alpha-2.
+    optional string language = 11;
 
-    // "Limit Ad Tracking" signal commercially endorsed (e.g., iOS, Android),
-    // where 0 = tracking is unrestricted, 1 = tracking must be limited per
-    // commercial guidelines.
-    // RECOMMENDED by the OpenRTB specification.
-    optional bool lmt = 23;
+    // Carrier or ISP (e.g., "VERIZON") using exchange curated string
+    // names which should be published to bidders a priori.
+    optional string carrier = 10;
 
     // Mobile carrier as the concatenated MCC-MNC code (e.g.,
     // "310-005" identifies Verizon Wireless CDMA in the USA).
@@ -1087,6 +1063,30 @@ message BidRequest {
     // and MNC parts is required to remove parsing ambiguity.
     optional string mccmnc = 30;
 
+    // Network connection type.
+    optional ConnectionType connectiontype = 17;
+
+    // ID sanctioned for advertiser use in the clear (i.e., not hashed).
+    optional string ifa = 20;
+
+    // Hardware device ID (e.g., IMEI); hashed via SHA1.
+    optional string didsha1 = 5;
+
+    // Hardware device ID (e.g., IMEI); hashed via MD5.
+    optional string didmd5 = 6;
+
+    // Platform device ID (e.g., Android ID); hashed via SHA1.
+    optional string dpidsha1 = 7;
+
+    // Platform device ID (e.g., Android ID); hashed via MD5.
+    optional string dpidmd5 = 8;
+
+    // MAC address of the device; hashed via SHA1.
+    optional string macsha1 = 21;
+
+    // MAC address of the device; hashed via MD5.
+    optional string macmd5 = 22;
+
     // Extensions.
     extensions 100 to 9999;
   }
@@ -1252,7 +1252,7 @@ message BidRequest {
   // ("COPPA"). Refer to Section 7.1 for more information.
   message Regs {
     // Flag indicating if this request is subject to the COPPA regulations
-    // established by the USA FTC, where 0 = no, 1 = yes.
+    // established by the USA FTC.
     optional bool coppa = 1;
 
     // Extensions.
@@ -1281,7 +1281,19 @@ message BidResponse {
   // Bidder generated response ID to assist with logging/tracking.
   optional string bidid = 3;
 
-  // Bid currency using ISO-4217 alpha codes.
+  // Bid currency using ISO-4217 alpha codes. This field will be required
+  // starting in Q4 2022. If this field is populated and differs from the
+  // bidding currency, the bid will be filtered. If this field is not populated,
+  // the currency will be assumed to be the bidding currency. The bidding
+  // currency is determined by:
+  // 1. The bidder-level currency, if configured in RTB account settings.
+  // 2. Otherwise, the currency of the buyer account indicated by the
+  // billing ID in the cid field of the bid response.
+  // 3. Otherwise, if cid is not populated in the bid response, the
+  // currency of the buyer account indicated by the sole billing ID in the
+  // bid request.
+  // The currency of the buyer account is set on account creation and can be
+  // checked by contacting a Technical Account Manager.
   optional string cur = 4;
 
   // Optional feature to allow a bidder to set data in the exchange's cookie.
@@ -1313,8 +1325,8 @@ message BidResponse {
     // IVT transparency reporting, given that it is no longer than 64 bytes.
     optional string seat = 2;
 
-    // 0 = impressions can be won individually; 1 = impressions must be won or
-    // lost as a group.
+    // false = impressions can be won individually;
+    // true = impressions must be won or lost as a group.
     optional bool group = 3 [default = false];
 
     // Extensions.
@@ -1340,13 +1352,24 @@ message BidResponse {
       // REQUIRED by the OpenRTB specification.
       required double price = 3;
 
-      // ID of a preloaded ad to be served if the bid wins.
-      optional string adid = 4;
-
       // Win notice URL called by the exchange if the bid wins; optional means
       // of serving ad markup.
       optional string nurl = 5;
 
+      // Billing notice URL called by the exchange when a winning bid
+      // becomes billable based on exchange-specific business policy
+      // (e.g., typically delivered, viewed, etc.). Substitution macros
+      // (Section 4.4) may be included.
+      optional string burl = 22;
+
+      // Loss notice URL called by the exchange when a bid is known to
+      // have been lost. Substitution macros (Section 4.4) may be
+      // included. Exchange-specific policy may preclude support for
+      // loss notices or the disclosure of winning clearing prices
+      // resulting in ${AUCTION_PRICE} macros being removed (i.e.,
+      // replaced with a zero-length string).
+      optional string lurl = 23;
+
       oneof adm_oneof {
         // Optional means of conveying ad markup in case the bid wins;
         // supersedes the win notice if markup is included in both.
@@ -1360,6 +1383,9 @@ message BidResponse {
         NativeResponse adm_native = 50;
       }
 
+      // ID of a preloaded ad to serve if the bid wins.
+      optional string adid = 4;
+
       // Advertiser domain for block list checking (e.g., "ford.com"). This can
       // be an array of for the case of rotating creatives. Exchanges can
       // mandate that only one domain is allowed.
@@ -1382,6 +1408,12 @@ message BidResponse {
       // Creative ID to assist with ad quality checking.
       optional string crid = 10;
 
+      // Tactic ID to enable buyers to label bids for reporting to the
+      // exchange the tactic through which their bid was submitted.
+      // The specific usage and meaning of the tactic ID should be
+      // communicated between buyer and exchanges a priori.
+      optional string tactic = 24;
+
       // IAB content categories of the creative.
       repeated string cat = 15;
 
@@ -1397,6 +1429,11 @@ message BidResponse {
       // Creative media rating per QAG guidelines.
       optional QAGMediaRating qagmediarating = 20;
 
+      // Language of the creative using ISO-639-1-alpha-2. The nonstandard
+      // code "xx" may also be used if the creative has no
+      // linguistic content (e.g., a banner with just a company logo).
+      optional string language = 25;
+
       // Reference to the deal.id from the bid request if this bid pertains to a
       // private marketplace direct deal.
       optional string dealid = 13;
@@ -1407,35 +1444,6 @@ message BidResponse {
       // Height of the creative in device independent pixels (DIPS).
       optional int32 h = 17;
 
-      // Advisory as to the number of seconds the bidder is willing to
-      // wait between the auction and the actual impression.
-      optional int32 exp = 21;
-
-      // Billing notice URL called by the exchange when a winning bid
-      // becomes billable based on exchange-specific business policy
-      // (e.g., typically delivered, viewed, etc.). Substitution macros
-      // (Section 4.4) may be included.
-      optional string burl = 22;
-
-      // Loss notice URL called by the exchange when a bid is known to
-      // have been lost. Substitution macros (Section 4.4) may be
-      // included. Exchange-specific policy may preclude support for
-      // loss notices or the disclosure of winning clearing prices
-      // resulting in ${AUCTION_PRICE} macros being removed (i.e.,
-      // replaced with a zero-length string).
-      optional string lurl = 23;
-
-      // Tactic ID to enable buyers to label bids for reporting to the
-      // exchange the tactic through which their bid was submitted.
-      // The specific usage and meaning of the tactic ID should be
-      // communicated between buyer and exchanges a priori.
-      optional string tactic = 24;
-
-      // Language of the creative using ISO-639-1-alpha-2. The nonstandard
-      // code "xx" may also be used if the creative has no
-      // linguistic content (e.g., a banner with just a company logo).
-      optional string language = 25;
-
       // Relative width of the creative when expressing size as a ratio.
       // Required for Flex Ads.
       optional int32 wratio = 26;
@@ -1444,6 +1452,10 @@ message BidResponse {
       // Required for Flex Ads.
       optional int32 hratio = 27;
 
+      // Advisory as to the number of seconds the bidder is willing to
+      // wait between the auction and the actual impression.
+      optional int32 exp = 21;
+
       // Extensions.
       extensions 100 to 9999;
     }
@@ -1454,25 +1466,12 @@ message BidResponse {
 // opportunity available for bid via this bid request. It must be included
 // directly in the impression object if the impression offered for auction
 // is a native ad format.
-// Note: Prior to VERSION 1.1, the specification could be interpreted as
-// requiring the native request to have a root node with a single field "native"
-// that would contain the NativeRequest as its value.
-// In 1.2 The NativeRequest Object specified here is now the root object.
 message NativeRequest {
   // Version of the Native Markup version in use.
   optional string ver = 1;
 
-  // The Layout ID of the native ad unit.
-  // RECOMMENDED by OpenRTB Native 1.0; optional in 1.1, DEPRECATED in 1.2.
-  optional LayoutId layout = 2;
-
-  // The Ad unit ID of the native ad unit.
-  // This corresponds to one of IAB Core-6 native ad units.
-  // RECOMMENDED by OpenRTB Native 1.0; optional in 1.1, DEPRECATED in 1.2.
-  optional AdUnitId adunit = 3;
-
   // The context in which the ad appears.
-  // RECOMMENDED in 1.2.
+  // RECOMMENDED by the OpenRTB Native specification.
   optional ContextType context = 7;
 
   // A more detailed context in which the ad appears.
@@ -1497,28 +1496,32 @@ message NativeRequest {
   repeated Asset assets = 6;
 
   // Whether the supply source / impression supports returning an assetsurl
-  // instead of an asset object. 0 or the absence of the field indicates no such
-  // support.
-  // Implemented in 1.2
+  // instead of an asset object. false or the absence of the field indicates no
+  // such support.
   optional bool aurlsupport = 11;
 
   // Whether the supply source / impression supports returning a DCO URL
-  // instead of an asset object. 0 or the absence of the field indicates no such
-  // support.
-  // Implemented in 1.2
-  // Beta feature.
+  // instead of an asset object. false or the absence of the field indicates no
+  // such support. Beta feature.
   optional bool durlsupport = 12;
 
   // Specifies what type of event tracking is supported.
-  // Implemented in 1.2
   repeated EventTrackers eventtrackers = 13;
 
-  // Set to 1 when the native ad supports buyer-specific privacy notice.
-  // Set to 0 (or field absent) when the native ad doesn't support custom
+  // Set to true when the native ad supports buyer-specific privacy notice.
+  // Set to false (or field absent) when the native ad doesn't support custom
   // privacy links or if support is unknown.
-  // RECOMMENDED and implemented in 1.2
+  // RECOMMENDED by the OpenRTB Native specification.
   optional bool privacy = 14;
 
+  // DEPRECATED in OpenRTB Native 1.1, REMOVED in 1.2+.
+  // Use field <code>plcmttype</code>.
+  optional LayoutId layout = 2 [deprecated = true];
+
+  // DEPRECATED in OpenRTB Native 1.1, REMOVED in 1.2+.
+  // Use fields <code>context</code> and <code>contextsubtype</code>.
+  optional AdUnitId adunit = 3 [deprecated = true];
+
   // Extensions.
   extensions 100 to 9999;
 
@@ -1648,13 +1651,9 @@ message NativeRequest {
 
 // OpenRTB Native 1.0: The native response object is the top level JSON object
 // which identifies an native response.
-// Note: Prior to VERSION 1.1, the native response's root node was an object
-// with a single field "native" that would contain the object above as its
-// value.
-// In 1.2 The NativeResponse Object specified here is now the root object.
 message NativeResponse {
   // Version of the Native Markup version in use.
-  // RECOMMENDED in 1.2
+  // RECOMMENDED by the OpenRTB Native specification.
   optional string ver = 1;
 
   // List of native ad's assets.
@@ -1666,7 +1665,6 @@ message NativeResponse {
   // JSON object mirroring the asset object in the bid response, subject to
   // certain requirements as specified in the individual objects.
   // Where present, overrides the assets object in the response.
-  // Implemented in 1.2
   optional string assetsurl = 6;
 
   // URL where a dynamic creative specification may be found for populating this
@@ -1676,7 +1674,6 @@ message NativeResponse {
   // the scope of this spec and must be agreed offline between parties or as may
   // be specified in a future revision of the Dynamic Content Ads spec.
   // Where present, overrides the assets object in the response.
-  // Implemented in 1.2
   optional string dcourl = 7;
 
   // Destination Link. This is default link object for the ad.
@@ -1687,25 +1684,23 @@ message NativeResponse {
   // REQUIRED by the OpenRTB Native specification.
   required Link link = 3;
 
+  // DEPRECATED in OpenRTB Native 1.2+. Prefer object <code>EventTracker</code>.
   // Array of impression tracking URLs, expected to return a 1x1 image or
   // 204 response - typically only passed when using 3rd party trackers.
-  // To be deprecated in 1.2 - Replaced with EventTracker.
-  repeated string imptrackers = 4;
+  repeated string imptrackers = 4 [deprecated = true];
 
+  // DEPRECATED in OpenRTB Native 1.2+. Prefer object <code>EventTracker</code>.
   // Optional javascript impression tracker. Contains <script> tags to be
   // executed at impression time where it can be supported.
-  // To be deprecated in 1.2 - Replaced with EventTracker.
-  optional string jstracker = 5;
+  optional string jstracker = 5 [deprecated = true];
 
   // Array of response event trackers to run with the ad, in response to the
   // declared supported methods in the NativeRequest. Replaces imptrackers and
   // jstrackers.
-  // Implemented in 1.2
   repeated EventTracker eventtrackers = 8;
 
   // If support was indicated in the request, URL of a page informing the user
   // about the buyer's targeting activity.
-  // Implemented in 1.2
   optional string privacy = 9;
 
   // Extensions.
@@ -1744,7 +1739,7 @@ message NativeResponse {
     // REQUIRED in 1.0, or in 1.2 if embedded asset is being used.
     required int32 id = 1;
 
-    // Set to 1 if asset is required. (bidder requires it to be displayed).
+    // Set to true if asset is required. (bidder requires it to be displayed).
     optional bool required = 2 [default = false];
 
     // RECOMMENDED by the OpenRTB Native specification.
@@ -1786,7 +1781,6 @@ message NativeResponse {
 
       // The length of the title being provided.
       // REQUIRED if using assetsurl/dcourl representation.
-      // Implemented in 1.2
       optional int32 len = 2;
 
       // Extensions.
@@ -1803,7 +1797,6 @@ message NativeResponse {
       // The type of image element being submitted from the ImageType enum.
       // REQUIRED for assetsurl or dcourl responses,
       // not required to embedded asset responses.
-      // Implemented in 1.2
       optional ImageAssetType type = 4;
 
       // URL of the image asset.
@@ -1834,18 +1827,16 @@ message NativeResponse {
     message Data {
       // The type of data element being submitted from the DataAssetTypes enum.
       // REQUIRED in 1.2 for assetsurl or dcourl responses.
-      // Implemented in 1.2.
       optional DataAssetType type = 3;
 
       // The length of the data element being submitted. Where applicable, must
       // comply with the recommended maximum lengths in the DataAssetType enum.
       // REQUIRED in 1.2 for assetsurl or dcourl responses.
-      // Implemented in 1.2.
       optional int32 len = 4;
 
+      // DEPRECATED in OpenRTB Native 1.2+. No replacement.
       // The optional formatted string name of the data type to be displayed.
-      // DEPRECATED in 1.2.
-      optional string label = 1;
+      optional string label = 1 [deprecated = true];
 
       // The formatted string of data to be displayed. Can contain a formatted
       // value such as "5 stars" or "$10" or "3.4 stars out of 5".
@@ -2385,20 +2376,27 @@ enum AdPosition {
 
   ABOVE_THE_FOLD = 1;
 
+  // DEPRECATED in OpenRTB 2.1+. No replacement.
   // May or may not be immediately visible depending on screen size and
   // resolution.
-  // @deprecated
-  DEPRECATED_LIKELY_BELOW_THE_FOLD = 2;
+  DEPRECATED_LIKELY_BELOW_THE_FOLD = 2 [deprecated = true];
 
   BELOW_THE_FOLD = 3;
 
   // [OpenRTB->AdX: SlotVisibility.ABOVE_THE_FOLD]
+  // Equivalent to
+  // `sticky_settings.top_horizontal_stickiness` in Authorized
+  // Buyers RTB protocol.
   HEADER = 4;
 
   // [OpenRTB->AdX: SlotVisibility.ABOVE_THE_FOLD]
+  // Equivalent to `sticky_settings.bottom_horizontal_stickiness` in Authorized
+  // Buyers RTB protocol.
   FOOTER = 5;
 
   // [OpenRTB->AdX: SlotVisibility.ABOVE_THE_FOLD]
+  // Equivalent to `sticky_settings.vertical_stickiness` in Authorized Buyers
+  // RTB protocol.
   SIDEBAR = 6;
 
   // [OpenRTB->AdX: SlotVisibility.ABOVE_THE_FOLD]
@@ -2723,9 +2721,7 @@ enum VolumeNormalizationMode {
 
 // ***** OpenRTB Native enums **************************************************
 
-// OpenRTB Native 1.0: Core layouts. An implementing exchange may not
-// support all asset variants or introduce new ones unique to that system.
-// To be deprecated.
+// DEPRECATED in OpenRTB Native 1.1, REMOVED in 1.2+.
 enum LayoutId {
   CONTENT_WALL = 1;
   APP_WALL = 2;
@@ -2737,13 +2733,7 @@ enum LayoutId {
   // Exchange-specific values above 500.
 }
 
-// OpenRTB Native 1.0: Below is a list of the core ad unit ids described by
-// IAB: http://www.iab.net/media/file/IABNativeAdvertisingPlaybook120413.pdf
-// In feed unit is essentially a layout, it has been removed from the list.
-// In feed units can be identified via the layout parameter on the request.
-// An implementing exchange may not support all asset variants or introduce
-// new ones unique to that system.
-// To be deprecated.
+// DEPRECATED in OpenRTB Native 1.1, REMOVED in 1.2+.
 enum AdUnitId {
   PAID_SEARCH_UNIT = 1;
   RECOMMENDATION_WIDGET = 2;
@@ -2881,10 +2871,9 @@ enum ImageAssetType {
   // Max height: at least 50; Aspect ratio: 1:1.
   ICON = 1;
 
+  // DEPRECATED in OpenRTB Native 1.2+. Prefer type <code>ICON</code>.
   // Logo image for the brand/app.
-  // To be deprecated in a future version - use type 1 / ICON.
-  // DEPRECATED in 1.2
-  LOGO = 2;
+  LOGO = 2 [deprecated = true];
 
   // Large image preview for the ad.
   // At least one of 2 size variants required:
diff --git a/pom.xml b/pom.xml
index ad27cb4d..7bea350b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -55,8 +55,8 @@
     <guavaVersion>31.1-jre</guavaVersion>
     <injectVersion>1</injectVersion>
     <junitVersion>4.13.2</junitVersion>
-    <metricsVersion>4.2.8</metricsVersion>
-    <protobufVersion>3.19.4</protobufVersion>
+    <metricsVersion>4.2.10</metricsVersion>
+    <protobufVersion>3.21.3</protobufVersion>
     <slf4jVersion>1.7.36</slf4jVersion>
     <truthVersion>1.1.3</truthVersion>