From ac846ccf5787b2058d0d72115e165f362c06ad65 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 20 May 2021 13:27:35 +0200
Subject: [PATCH 1/2] remove duplicate checks

---
 modules/core/02-client/types/proposal.go             | 4 ----
 modules/light-clients/07-tendermint/types/upgrade.go | 6 +-----
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/modules/core/02-client/types/proposal.go b/modules/core/02-client/types/proposal.go
index 3d10a925f5b..612342287a4 100644
--- a/modules/core/02-client/types/proposal.go
+++ b/modules/core/02-client/types/proposal.go
@@ -111,10 +111,6 @@ func (up *UpgradeProposal) ValidateBasic() error {
 		return err
 	}
 
-	if up.Plan.Height <= 0 {
-		return sdkerrors.Wrap(ErrInvalidUpgradeProposal, "IBC chain upgrades must set a positive height")
-	}
-
 	if up.UpgradedClientState == nil {
 		return sdkerrors.Wrap(ErrInvalidUpgradeProposal, "upgraded client state cannot be nil")
 	}
diff --git a/modules/light-clients/07-tendermint/types/upgrade.go b/modules/light-clients/07-tendermint/types/upgrade.go
index ab5ebcf4148..e2a3d87be70 100644
--- a/modules/light-clients/07-tendermint/types/upgrade.go
+++ b/modules/light-clients/07-tendermint/types/upgrade.go
@@ -6,10 +6,10 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	upgradetypes "github.com/cosmos/cosmos-sdk/x/upgrade/types"
 	clienttypes "github.com/cosmos/ibc-go/modules/core/02-client/types"
 	commitmenttypes "github.com/cosmos/ibc-go/modules/core/23-commitment/types"
 	"github.com/cosmos/ibc-go/modules/core/exported"
-	upgradetypes "github.com/cosmos/cosmos-sdk/x/upgrade/types"
 )
 
 // VerifyUpgradeAndUpdateState checks if the upgraded client has been committed by the current client
@@ -71,10 +71,6 @@ func (cs ClientState) VerifyUpgradeAndUpdateState(
 		return nil, nil, sdkerrors.Wrap(err, "could not retrieve consensus state for lastHeight")
 	}
 
-	if cs.IsExpired(consState.Timestamp, ctx.BlockTime()) {
-		return nil, nil, sdkerrors.Wrap(clienttypes.ErrInvalidClient, "cannot upgrade an expired client")
-	}
-
 	// Verify client proof
 	bz, err := cdc.MarshalInterface(upgradedClient)
 	if err != nil {

From d8c5de7712501d8d3e9155910f06ed353c578b3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Colin=20Axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 20 May 2021 13:28:55 +0200
Subject: [PATCH 2/2] changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8119e1019a7..d790d6c00d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -65,6 +65,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (07-tendermint) [\#182](https://github.com/cosmos/ibc-go/pull/182) Remove duplicate checks in upgrade logic.
 * (modules/core/04-channel) [\#7949](https://github.com/cosmos/cosmos-sdk/issues/7949) Standardized channel `Acknowledgement` moved to its own file. Codec registration redundancy removed.
 * (modules/core/04-channel) [\#144](https://github.com/cosmos/ibc-go/pull/144) Introduced a `packet_data_hex` attribute to emit the hex-encoded packet data in events. This allows for raw binary (proto-encoded message) to be sent over events and decoded correctly on relayer. Original `packet_data` is DEPRECATED. All relayers and IBC event consumers are encouraged to switch to `packet_data_hex` as soon as possible.
 * (modules/light-clients/07-tendermint) [\#125](https://github.com/cosmos/ibc-go/pull/125) Implement efficient iteration of consensus states and pruning of earliest expired consensus state on UpdateClient.