diff --git a/polkadot/runtime/kusama/src/lib.rs b/polkadot/runtime/kusama/src/lib.rs
index 739dcdcd14..b908ea9d8a 100644
--- a/polkadot/runtime/kusama/src/lib.rs
+++ b/polkadot/runtime/kusama/src/lib.rs
@@ -260,7 +260,6 @@ parameter_types! {
 	pub const UncleGenerations: u32 = 0;
 }
 
-// TODO: substrate#2986 implement this properly
 impl pallet_authorship::Config for Runtime {
 	type FindAuthor = pallet_session::FindAccountFromAuthorIndex<Self, Babe>;
 	type UncleGenerations = UncleGenerations;
diff --git a/polkadot/runtime/rococo/src/lib.rs b/polkadot/runtime/rococo/src/lib.rs
index 35f1942d83..da66665fc4 100644
--- a/polkadot/runtime/rococo/src/lib.rs
+++ b/polkadot/runtime/rococo/src/lib.rs
@@ -496,7 +496,6 @@ parameter_types! {
 	pub const UncleGenerations: u32 = 0;
 }
 
-// TODO: substrate#2986 implement this properly
 impl pallet_authorship::Config for Runtime {
 	type FindAuthor = pallet_session::FindAccountFromAuthorIndex<Self, Babe>;
 	type UncleGenerations = UncleGenerations;
diff --git a/polkadot/runtime/test-runtime/src/lib.rs b/polkadot/runtime/test-runtime/src/lib.rs
index dafde1d74e..e76a08186c 100644
--- a/polkadot/runtime/test-runtime/src/lib.rs
+++ b/polkadot/runtime/test-runtime/src/lib.rs
@@ -242,7 +242,6 @@ parameter_types! {
 	pub storage UncleGenerations: u32 = 0;
 }
 
-// TODO: substrate#2986 implement this properly
 impl pallet_authorship::Config for Runtime {
 	type FindAuthor = pallet_session::FindAccountFromAuthorIndex<Self, Babe>;
 	type UncleGenerations = UncleGenerations;
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index a5a75ccdb0..955d5dd8ee 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -264,7 +264,6 @@ parameter_types! {
 	pub const UncleGenerations: u32 = 0;
 }
 
-// TODO: substrate#2986 implement this properly
 impl pallet_authorship::Config for Runtime {
 	type FindAuthor = pallet_session::FindAccountFromAuthorIndex<Self, Babe>;
 	type UncleGenerations = UncleGenerations;