diff --git a/client-gui2 b/client-gui2
index f40aa6bf..b76f9b43 160000
--- a/client-gui2
+++ b/client-gui2
@@ -1 +1 @@
-Subproject commit f40aa6bfd0f4d0a9096d7f663ec1bce895ae13ce
+Subproject commit b76f9b430b6a4f60180e715c71fe1caa99b022ed
diff --git a/common/proto/accounting.proto b/common/proto/accounting.proto
index e06370a4..55df4b19 100644
--- a/common/proto/accounting.proto
+++ b/common/proto/accounting.proto
@@ -360,6 +360,7 @@ message ConfigureAccountingPeriodRequest {
 
 message CloseAccountingPeriodRequest {
   int64 period_id = 1;
+  string revaluation_preview = 2;
 }
 
 message ReopenAccountingPeriodRequest {
@@ -409,6 +410,7 @@ message AccountingPeriod {
 
 message ListPeriodBalancesRequest {
   int64 period_id = 1;
+  bool preview_revaluation = 2;
 }
 
 message PeriodBalance {
@@ -440,6 +442,9 @@ message PeriodDenominationBalance {
 message ListPeriodBalancesResponse {
   repeated PeriodBalance balances = 1;
   repeated PeriodDenominationBalance denomination_balances = 2;
+  // JSON array of proposed valuations for an open period, or the frozen
+  // evidence for a closed period. Pass the open-period value unchanged to close.
+  string revaluation_preview = 3;
 }
 
 message GetTrialBalanceRequest {
diff --git a/common/src/proto/descriptor.bin b/common/src/proto/descriptor.bin
index 60f31304..9f81056d 100644
Binary files a/common/src/proto/descriptor.bin and b/common/src/proto/descriptor.bin differ
diff --git a/common/src/proto/komp_ac.accounting.rs b/common/src/proto/komp_ac.accounting.rs
index 31e247b2..ea5f7d50 100644
--- a/common/src/proto/komp_ac.accounting.rs
+++ b/common/src/proto/komp_ac.accounting.rs
@@ -368,10 +368,12 @@ pub struct ConfigureAccountingPeriodRequest {
     pub period_end: ::prost::alloc::string::String,
 }
 #[derive(serde::Serialize, serde::Deserialize)]
-#[derive(Clone, Copy, PartialEq, Eq, Hash, ::prost::Message)]
+#[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
 pub struct CloseAccountingPeriodRequest {
     #[prost(int64, tag = "1")]
     pub period_id: i64,
+    #[prost(string, tag = "2")]
+    pub revaluation_preview: ::prost::alloc::string::String,
 }
 #[derive(serde::Serialize, serde::Deserialize)]
 #[derive(Clone, Copy, PartialEq, Eq, Hash, ::prost::Message)]
@@ -450,6 +452,8 @@ pub struct AccountingPeriod {
 pub struct ListPeriodBalancesRequest {
     #[prost(int64, tag = "1")]
     pub period_id: i64,
+    #[prost(bool, tag = "2")]
+    pub preview_revaluation: bool,
 }
 #[derive(serde::Serialize, serde::Deserialize)]
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
@@ -500,6 +504,10 @@ pub struct ListPeriodBalancesResponse {
     pub balances: ::prost::alloc::vec::Vec<PeriodBalance>,
     #[prost(message, repeated, tag = "2")]
     pub denomination_balances: ::prost::alloc::vec::Vec<PeriodDenominationBalance>,
+    /// JSON array of proposed valuations for an open period, or the frozen
+    /// evidence for a closed period. Pass the open-period value unchanged to close.
+    #[prost(string, tag = "3")]
+    pub revaluation_preview: ::prost::alloc::string::String,
 }
 #[derive(serde::Serialize, serde::Deserialize)]
 #[derive(Clone, Copy, PartialEq, Eq, Hash, ::prost::Message)]
diff --git a/komp-app/src/grpc.rs b/komp-app/src/grpc.rs
index 6908fae5..5bfee161 100644
--- a/komp-app/src/grpc.rs
+++ b/komp-app/src/grpc.rs
@@ -264,8 +264,8 @@ impl GrpcClient {
             .context("gRPC ConfigureAccountingPeriod call failed")?.into_inner())
     }
 
-    pub async fn close_accounting_period(&mut self, period_id: i64) -> Result<AccountingPeriod> {
-        let request = self.authenticated_request(CloseAccountingPeriodRequest { period_id })?;
+    pub async fn close_accounting_period(&mut self, period_id: i64, revaluation_preview: String) -> Result<AccountingPeriod> {
+        let request = self.authenticated_request(CloseAccountingPeriodRequest { period_id, revaluation_preview })?;
         Ok(self.accounting_client.close_accounting_period(request).await
             .context("gRPC CloseAccountingPeriod call failed")?.into_inner())
     }
@@ -297,8 +297,8 @@ impl GrpcClient {
             .context("gRPC ListAccountingPeriods call failed")?.into_inner())
     }
 
-    pub async fn list_period_balances(&mut self, period_id: i64) -> Result<ListPeriodBalancesResponse> {
-        let request = self.authenticated_request(ListPeriodBalancesRequest { period_id })?;
+    pub async fn list_period_balances(&mut self, period_id: i64, preview_revaluation: bool) -> Result<ListPeriodBalancesResponse> {
+        let request = self.authenticated_request(ListPeriodBalancesRequest { period_id, preview_revaluation })?;
         Ok(self.accounting_client.list_period_balances(request).await
             .context("gRPC ListPeriodBalances call failed")?.into_inner())
     }
diff --git a/server b/server
index 239c2f35..f3ff9392 160000
--- a/server
+++ b/server
@@ -1 +1 @@
-Subproject commit 239c2f3539de6fa11d225da4485f9e025e4abb63
+Subproject commit f3ff9392236ac4c5d232a2ee3d41ef76e9355fcb