diff --git a/chain/actors/policy/policy.go b/chain/actors/policy/policy.go
index 4d115f783..bb35025ec 100644
--- a/chain/actors/policy/policy.go
+++ b/chain/actors/policy/policy.go
@@ -92,6 +92,13 @@ func AddSupportedProofTypes(types ...abi.RegisteredSealProof) {
 		miner4.PreCommitSealProofTypesV8[t+abi.RegisteredSealProof_StackedDrg2KiBV1_1] = struct{}{}
 
 		miner5.PreCommitSealProofTypesV8[t+abi.RegisteredSealProof_StackedDrg2KiBV1_1] = struct{}{}
+		wpp, err := t.RegisteredWindowPoStProof()
+		if err != nil {
+			// Fine to panic, this is a test-only method
+			panic(err)
+		}
+
+		miner5.WindowPoStProofTypes[wpp] = struct{}{}
 
 	}
 }
diff --git a/chain/actors/policy/policy.go.template b/chain/actors/policy/policy.go.template
index aef1081cb..cd2eca4ea 100644
--- a/chain/actors/policy/policy.go.template
+++ b/chain/actors/policy/policy.go.template
@@ -62,6 +62,13 @@ func AddSupportedProofTypes(types ...abi.RegisteredSealProof) {
                 miner{{.}}.PreCommitSealProofTypesV8[t+abi.RegisteredSealProof_StackedDrg2KiBV1_1] = struct{}{}
             {{else}}
                 miner{{.}}.PreCommitSealProofTypesV8[t+abi.RegisteredSealProof_StackedDrg2KiBV1_1] = struct{}{}
+                wpp, err := t.RegisteredWindowPoStProof()
+                if err != nil {
+                    // Fine to panic, this is a test-only method
+                    panic(err)
+                }
+
+                miner{{.}}.WindowPoStProofTypes[wpp] = struct{}{}
             {{end}}
         {{end}}
 	}
diff --git a/storage/wdpost_run.go b/storage/wdpost_run.go
index fd7c4f184..ca149aec3 100644
--- a/storage/wdpost_run.go
+++ b/storage/wdpost_run.go
@@ -497,9 +497,14 @@ func (s *WindowPoStScheduler) runPost(ctx context.Context, di dline.Info, ts *ty
 		return nil, xerrors.Errorf("getting partitions: %w", err)
 	}
 
+	nv, err := s.api.StateNetworkVersion(ctx, ts.Key())
+	if err != nil {
+		return nil, xerrors.Errorf("getting network version: %w", err)
+	}
+
 	// Split partitions into batches, so as not to exceed the number of sectors
 	// allowed in a single message
-	partitionBatches, err := s.batchPartitions(partitions)
+	partitionBatches, err := s.batchPartitions(partitions, nv)
 	if err != nil {
 		return nil, err
 	}
@@ -679,7 +684,7 @@ func (s *WindowPoStScheduler) runPost(ctx context.Context, di dline.Info, ts *ty
 	return posts, nil
 }
 
-func (s *WindowPoStScheduler) batchPartitions(partitions []api.Partition) ([][]api.Partition, error) {
+func (s *WindowPoStScheduler) batchPartitions(partitions []api.Partition, nv network.Version) ([][]api.Partition, error) {
 	// We don't want to exceed the number of sectors allowed in a message.
 	// So given the number of sectors in a partition, work out the number of
 	// partitions that can be in a message without exceeding sectors per
@@ -695,6 +700,11 @@ func (s *WindowPoStScheduler) batchPartitions(partitions []api.Partition) ([][]a
 		return nil, xerrors.Errorf("getting sectors per partition: %w", err)
 	}
 
+	// Also respect the AddressedPartitionsMax (which is the same as DeclarationsMax (which is all really just MaxPartitionsPerDeadline))
+	if partitionsPerMsg > policy.GetDeclarationsMax(nv) {
+		partitionsPerMsg = policy.GetDeclarationsMax(nv)
+	}
+
 	// The number of messages will be:
 	// ceiling(number of partitions / partitions per message)
 	batchCount := len(partitions) / partitionsPerMsg
diff --git a/storage/wdpost_run_test.go b/storage/wdpost_run_test.go
index 5117e718a..f80f6bee2 100644
--- a/storage/wdpost_run_test.go
+++ b/storage/wdpost_run_test.go
@@ -5,6 +5,9 @@ import (
 	"context"
 	"testing"
 
+	builtin5 "github.com/filecoin-project/specs-actors/v5/actors/builtin"
+	miner5 "github.com/filecoin-project/specs-actors/v5/actors/builtin/miner"
+
 	"github.com/stretchr/testify/require"
 	"golang.org/x/xerrors"
 
@@ -177,13 +180,16 @@ func TestWDPostDoPost(t *testing.T) {
 	mockStgMinerAPI := newMockStorageMinerAPI()
 
 	// Get the number of sectors allowed in a partition for this proof type
-	sectorsPerPartition, err := builtin2.PoStProofWindowPoStPartitionSectors(proofType)
+	sectorsPerPartition, err := builtin5.PoStProofWindowPoStPartitionSectors(proofType)
 	require.NoError(t, err)
 	// Work out the number of partitions that can be included in a message
 	// without exceeding the message sector limit
 
 	require.NoError(t, err)
-	partitionsPerMsg := int(miner2.AddressedSectorsMax / sectorsPerPartition)
+	partitionsPerMsg := int(miner5.AddressedSectorsMax / sectorsPerPartition)
+	if partitionsPerMsg > miner5.AddressedPartitionsMax {
+		partitionsPerMsg = miner5.AddressedPartitionsMax
+	}
 
 	// Enough partitions to fill expectedMsgCount-1 messages
 	partitionCount := (expectedMsgCount - 1) * partitionsPerMsg
@@ -219,11 +225,11 @@ func TestWDPostDoPost(t *testing.T) {
 	}
 
 	di := &dline.Info{
-		WPoStPeriodDeadlines:   miner2.WPoStPeriodDeadlines,
-		WPoStProvingPeriod:     miner2.WPoStProvingPeriod,
-		WPoStChallengeWindow:   miner2.WPoStChallengeWindow,
-		WPoStChallengeLookback: miner2.WPoStChallengeLookback,
-		FaultDeclarationCutoff: miner2.FaultDeclarationCutoff,
+		WPoStPeriodDeadlines:   miner5.WPoStPeriodDeadlines,
+		WPoStProvingPeriod:     miner5.WPoStProvingPeriod,
+		WPoStChallengeWindow:   miner5.WPoStChallengeWindow,
+		WPoStChallengeLookback: miner5.WPoStChallengeLookback,
+		FaultDeclarationCutoff: miner5.FaultDeclarationCutoff,
 	}
 	ts := mockTipSet(t)