diff --git a/proto/cmp/services/accommodation/v1/info.proto b/proto/cmp/services/accommodation/v1/info.proto
index 7ebde03..964a04c 100644
--- a/proto/cmp/services/accommodation/v1/info.proto
+++ b/proto/cmp/services/accommodation/v1/info.proto
@@ -13,7 +13,10 @@ message AccommodationProductInfoRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 
   // Languages
diff --git a/proto/cmp/services/accommodation/v1/list.proto b/proto/cmp/services/accommodation/v1/list.proto
index 4a3a785..646edb0 100644
--- a/proto/cmp/services/accommodation/v1/list.proto
+++ b/proto/cmp/services/accommodation/v1/list.proto
@@ -11,7 +11,10 @@ message AccommodationProductListRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 }
 
diff --git a/proto/cmp/services/accommodation/v1/property_types.proto b/proto/cmp/services/accommodation/v1/property_types.proto
index 41f2440..87d9be0 100644
--- a/proto/cmp/services/accommodation/v1/property_types.proto
+++ b/proto/cmp/services/accommodation/v1/property_types.proto
@@ -23,7 +23,10 @@ import "google/protobuf/timestamp.proto";
 message Property {
   // Ex: "2023-08-28T12:03:50", specifying when the static data of a product was
   // last updated
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 1;
 
   // Supplier product Code
diff --git a/proto/cmp/services/accommodation/v2/info.proto b/proto/cmp/services/accommodation/v2/info.proto
index 5e229a3..1c6a6d6 100644
--- a/proto/cmp/services/accommodation/v2/info.proto
+++ b/proto/cmp/services/accommodation/v2/info.proto
@@ -13,7 +13,10 @@ message AccommodationProductInfoRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 
   // Languages
diff --git a/proto/cmp/services/accommodation/v2/list.proto b/proto/cmp/services/accommodation/v2/list.proto
index f8fa569..ad8bdf4 100644
--- a/proto/cmp/services/accommodation/v2/list.proto
+++ b/proto/cmp/services/accommodation/v2/list.proto
@@ -11,7 +11,10 @@ message AccommodationProductListRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 }
 
diff --git a/proto/cmp/services/accommodation/v2/property_types.proto b/proto/cmp/services/accommodation/v2/property_types.proto
index 975779a..7b7c41a 100644
--- a/proto/cmp/services/accommodation/v2/property_types.proto
+++ b/proto/cmp/services/accommodation/v2/property_types.proto
@@ -23,7 +23,10 @@ import "google/protobuf/timestamp.proto";
 message Property {
   // Ex: "2023-08-28T12:03:50", specifying when the static data of a product was
   // last updated
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 1;
 
   // Supplier product Code
diff --git a/proto/cmp/services/activity/v1/activity_types.proto b/proto/cmp/services/activity/v1/activity_types.proto
index f830b2d..246dd86 100644
--- a/proto/cmp/services/activity/v1/activity_types.proto
+++ b/proto/cmp/services/activity/v1/activity_types.proto
@@ -29,7 +29,10 @@ message Activity {
 
   // Ex: "2023-08-28T12:03:50", specifying when the static data of a product was
   // last updated
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 2;
 
   // An identifier for external sessions, aiding in tracking and continuity across
@@ -91,7 +94,10 @@ message PickupDropoffEvent {
   string other_info = 4;
 
   // Datetime of the pickup dropoff event as Unix timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp date_time = 5;
 
   // Longitude and Latitude of the location
diff --git a/proto/cmp/services/activity/v1/info.proto b/proto/cmp/services/activity/v1/info.proto
index 94a5062..ab7e636 100644
--- a/proto/cmp/services/activity/v1/info.proto
+++ b/proto/cmp/services/activity/v1/info.proto
@@ -14,7 +14,10 @@ message ActivityProductInfoRequest {
 
   // Only respond with the products that are new, modified or deactivated after this
   // timestamp.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 
   // Languages to be included in the response for descriptions. Null means all
diff --git a/proto/cmp/services/activity/v1/list.proto b/proto/cmp/services/activity/v1/list.proto
index b84a81c..788bda4 100644
--- a/proto/cmp/services/activity/v1/list.proto
+++ b/proto/cmp/services/activity/v1/list.proto
@@ -11,7 +11,10 @@ message ActivityProductListRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 }
 
diff --git a/proto/cmp/services/activity/v2/activity_types.proto b/proto/cmp/services/activity/v2/activity_types.proto
index 35a7075..60bf07c 100644
--- a/proto/cmp/services/activity/v2/activity_types.proto
+++ b/proto/cmp/services/activity/v2/activity_types.proto
@@ -29,7 +29,10 @@ message Activity {
 
   // Ex: "2023-08-28T12:03:50", specifying when the static data of a product was
   // last updated
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 2;
 
   // An identifier for external sessions, aiding in tracking and continuity across
@@ -91,7 +94,10 @@ message PickupDropoffEvent {
   string other_info = 4;
 
   // Datetime of the pickup dropoff event as Unix timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp date_time = 5;
 
   // Longitude and Latitude of the location
diff --git a/proto/cmp/services/activity/v2/info.proto b/proto/cmp/services/activity/v2/info.proto
index e230587..16bcc60 100644
--- a/proto/cmp/services/activity/v2/info.proto
+++ b/proto/cmp/services/activity/v2/info.proto
@@ -14,7 +14,10 @@ message ActivityProductInfoRequest {
 
   // Only respond with the products that are new, modified or deactivated after this
   // timestamp.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 
   // Languages to be included in the response for descriptions. Null means all
diff --git a/proto/cmp/services/activity/v2/list.proto b/proto/cmp/services/activity/v2/list.proto
index df45c7d..807782e 100644
--- a/proto/cmp/services/activity/v2/list.proto
+++ b/proto/cmp/services/activity/v2/list.proto
@@ -11,7 +11,10 @@ message ActivityProductListRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 }
 
diff --git a/proto/cmp/services/book/v1/mint.proto b/proto/cmp/services/book/v1/mint.proto
index 832b35e..7a62654 100644
--- a/proto/cmp/services/book/v1/mint.proto
+++ b/proto/cmp/services/book/v1/mint.proto
@@ -58,7 +58,10 @@ message MintResponse {
   string provider_booking_reference = 4;
 
   // Timestamp of the booking in the inventory system of the supplier.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp provider_booking_timestamp = 5;
 
   // Price of the `BookingToken`. This field is meant to be populated by the
@@ -74,7 +77,10 @@ message MintResponse {
 
   // On chain booking token should be only buyable until this timestamp and should
   // expire after that.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp buyable_until = 9;
 
   // Transaction ID of the buy operation. This field is populated by the distributor
diff --git a/proto/cmp/services/book/v2/mint.proto b/proto/cmp/services/book/v2/mint.proto
index bd10b49..bd9f32e 100644
--- a/proto/cmp/services/book/v2/mint.proto
+++ b/proto/cmp/services/book/v2/mint.proto
@@ -57,7 +57,10 @@ message MintResponse {
   string provider_booking_reference = 4;
 
   // Timestamp of the booking in the inventory system of the supplier.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp provider_booking_timestamp = 5;
 
   // Price of the `BookingToken`. This field is meant to be populated by the
@@ -79,7 +82,10 @@ message MintResponse {
 
   // On chain booking token should be only buyable until this timestamp and should
   // expire after that.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp buyable_until = 10;
 
   // Transaction ID of the buy operation. This field is populated by the distributor
diff --git a/proto/cmp/services/info/v1/entry_requirements.proto b/proto/cmp/services/info/v1/entry_requirements.proto
index a7a40be..f9a2a42 100644
--- a/proto/cmp/services/info/v1/entry_requirements.proto
+++ b/proto/cmp/services/info/v1/entry_requirements.proto
@@ -105,7 +105,10 @@ message CountryEntryRequirementItem {
   cmp.services.info.v1.ItemStatus status = 3;
 
   // Significant update date
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_significant_update = 4;
 }
 
diff --git a/proto/cmp/services/info/v2/entry_requirements.proto b/proto/cmp/services/info/v2/entry_requirements.proto
index 6cdde1d..e6f3853 100644
--- a/proto/cmp/services/info/v2/entry_requirements.proto
+++ b/proto/cmp/services/info/v2/entry_requirements.proto
@@ -105,7 +105,10 @@ message CountryEntryRequirementItem {
   cmp.services.info.v2.ItemStatus status = 3;
 
   // Significant update date
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_significant_update = 4;
 }
 
diff --git a/proto/cmp/services/insurance/v1/info.proto b/proto/cmp/services/insurance/v1/info.proto
index 796a226..4abe39f 100644
--- a/proto/cmp/services/insurance/v1/info.proto
+++ b/proto/cmp/services/insurance/v1/info.proto
@@ -14,7 +14,10 @@ message InsuranceProductInfoRequest {
 
   // Only respond with the products that are new, modified or deactivated after this
   // timestamp.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 
   // Languages to be included in the response for descriptions. Null means all
diff --git a/proto/cmp/services/insurance/v1/insurance_types.proto b/proto/cmp/services/insurance/v1/insurance_types.proto
index 2ceb0cc..6993b7f 100644
--- a/proto/cmp/services/insurance/v1/insurance_types.proto
+++ b/proto/cmp/services/insurance/v1/insurance_types.proto
@@ -38,7 +38,10 @@ message Policy {
 
   // Ex: "2023-08-28T12:03:50", specifying when the static data of a product was
   // last updated
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 3;
 }
 
diff --git a/proto/cmp/services/insurance/v1/list.proto b/proto/cmp/services/insurance/v1/list.proto
index 8bbb968..6568c88 100644
--- a/proto/cmp/services/insurance/v1/list.proto
+++ b/proto/cmp/services/insurance/v1/list.proto
@@ -11,7 +11,10 @@ message InsuranceProductListRequest {
   cmp.types.v1.RequestHeader header = 1;
 
   // Only respond with the products that are modified after this timestamp
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp modified_after = 2;
 }
 
diff --git a/proto/cmp/services/ping/v1/ping.proto b/proto/cmp/services/ping/v1/ping.proto
index 3360525..19de947 100644
--- a/proto/cmp/services/ping/v1/ping.proto
+++ b/proto/cmp/services/ping/v1/ping.proto
@@ -17,7 +17,10 @@ message PingRequest {
   string ping_message = 2;
 
   // DateTime of the ping request
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp timestamp = 3;
 }
 
@@ -29,7 +32,10 @@ message PingResponse {
   string ping_message = 2;
 
   // DateTime of the ping response
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp timestamp = 3;
 }
 
diff --git a/proto/cmp/services/transport/v1/trip_types.proto b/proto/cmp/services/transport/v1/trip_types.proto
index e212ed5..dc72255 100644
--- a/proto/cmp/services/transport/v1/trip_types.proto
+++ b/proto/cmp/services/transport/v1/trip_types.proto
@@ -25,7 +25,10 @@ message Trip {
 // Represents a departure or arrival event
 message TransitEvent {
   // Date time of the event
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp date_time = 1;
 
   // Event location
diff --git a/proto/cmp/services/transport/v2/trip_types.proto b/proto/cmp/services/transport/v2/trip_types.proto
index 82d92bb..e44541a 100644
--- a/proto/cmp/services/transport/v2/trip_types.proto
+++ b/proto/cmp/services/transport/v2/trip_types.proto
@@ -25,7 +25,10 @@ message Trip {
 // Represents a departure or arrival event
 message TransitEvent {
   // Date time of the event
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp date_time = 1;
 
   // Event location
diff --git a/proto/cmp/types/v1/cancel_policy.proto b/proto/cmp/types/v1/cancel_policy.proto
index da3ee50..a44669c 100644
--- a/proto/cmp/types/v1/cancel_policy.proto
+++ b/proto/cmp/types/v1/cancel_policy.proto
@@ -22,7 +22,10 @@ message CancelPolicy {
 
   // The "free cancellation upto" identifier specifies the exact DateTime upto when
   // this booking can be cancelled free of charge.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp free_cancellation_upto = 2;
 
   // Full cancellation policies can be complex and extensive. Inclusion in search
diff --git a/proto/cmp/types/v1/change_policy.proto b/proto/cmp/types/v1/change_policy.proto
index e81d970..fc8876c 100644
--- a/proto/cmp/types/v1/change_policy.proto
+++ b/proto/cmp/types/v1/change_policy.proto
@@ -21,7 +21,10 @@ message ChangePolicy {
 
   // The "free change upto" identifier specifies the exact DateTime upto when
   // this search result can be changed free of charge.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp free_change_upto = 2;
 
   // Full change policies can be complex and extensive. Inclusion in search
diff --git a/proto/cmp/types/v1/datetime_range.proto b/proto/cmp/types/v1/datetime_range.proto
index f1ebf40..28339cf 100644
--- a/proto/cmp/types/v1/datetime_range.proto
+++ b/proto/cmp/types/v1/datetime_range.proto
@@ -10,8 +10,14 @@ import "google/protobuf/timestamp.proto";
 //
 // [Open Message Diagram](https://storage.googleapis.com/docs-cmp-files/diagrams/proto/cmp/types/v1/datetime_range.proto.dot.svg)
 message DateTimeRange {
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp start_datetime = 1;
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp end_datetime = 2;
 }
diff --git a/proto/cmp/types/v1/file.proto b/proto/cmp/types/v1/file.proto
index 8c88600..9193378 100644
--- a/proto/cmp/types/v1/file.proto
+++ b/proto/cmp/types/v1/file.proto
@@ -15,7 +15,10 @@ message File {
   string url = 2;
 
   // Last modification time
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 3;
 }
 
diff --git a/proto/cmp/types/v2/cancel_policy.proto b/proto/cmp/types/v2/cancel_policy.proto
index f69f2d1..bb02f36 100644
--- a/proto/cmp/types/v2/cancel_policy.proto
+++ b/proto/cmp/types/v2/cancel_policy.proto
@@ -22,7 +22,10 @@ message CancelPolicy {
 
   // The "free cancellation upto" identifier specifies the exact DateTime upto when
   // this booking can be cancelled free of charge.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp free_cancellation_upto = 2;
 
   // Full cancellation policies can be complex and extensive. Inclusion in search
diff --git a/proto/cmp/types/v2/change_policy.proto b/proto/cmp/types/v2/change_policy.proto
index bf1ff33..c9f2b28 100644
--- a/proto/cmp/types/v2/change_policy.proto
+++ b/proto/cmp/types/v2/change_policy.proto
@@ -21,7 +21,10 @@ message ChangePolicy {
 
   // The "free change upto" identifier specifies the exact DateTime upto when
   // this search result can be changed free of charge.
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp free_change_upto = 2;
 
   // Full change policies can be complex and extensive. Inclusion in search
diff --git a/proto/cmp/types/v2/file.proto b/proto/cmp/types/v2/file.proto
index 2c6ce72..a8a5092 100644
--- a/proto/cmp/types/v2/file.proto
+++ b/proto/cmp/types/v2/file.proto
@@ -15,7 +15,10 @@ message File {
   string url = 2;
 
   // Last modification time
-  // For any on-chain transactions, if applicable, nanoseconds will be ignored
+  //
+  // Timestamps may be used for both off-chain and on-chain operations.
+  // For on-chain operations, only seconds are supported, and nanoseconds
+  // will be ignored.
   google.protobuf.Timestamp last_modified = 3;
 }