diff --git a/Cargo.lock b/Cargo.lock
index ab24ada..ddf3c11 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -94,6 +94,7 @@ name = "bot"
 version = "0.1.4"
 dependencies = [
  "anyhow",
+ "chrono",
  "clap",
  "dptree",
  "eh2telegraph",
@@ -103,7 +104,7 @@ dependencies = [
  "serde",
  "singleflight-async",
  "teloxide",
- "time",
+ "time 0.3.9",
  "tokio",
  "tracing",
  "tracing-subscriber",
@@ -140,8 +141,11 @@ version = "0.4.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
 dependencies = [
+ "libc",
  "num-integer",
  "num-traits",
+ "time 0.1.44",
+ "winapi",
 ]
 
 [[package]]
@@ -1645,6 +1649,17 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi 0.10.0+wasi-snapshot-preview1",
+ "winapi",
+]
+
 [[package]]
 name = "time"
 version = "0.3.9"
@@ -1830,7 +1845,7 @@ dependencies = [
  "sharded-slab",
  "smallvec",
  "thread_local",
- "time",
+ "time 0.3.9",
  "tracing-core",
  "tracing-log",
 ]
@@ -1924,7 +1939,7 @@ dependencies = [
  "rustc_version",
  "rustversion",
  "thiserror",
- "time",
+ "time 0.3.9",
 ]
 
 [[package]]
@@ -1949,6 +1964,12 @@ version = "0.9.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
diff --git a/bot/Cargo.toml b/bot/Cargo.toml
index 645f1ab..d95d637 100644
--- a/bot/Cargo.toml
+++ b/bot/Cargo.toml
@@ -8,6 +8,7 @@ eh2telegraph = {path = "../eh2telegraph"}
 
 anyhow = "1"
 clap = {version = "3", features = ["derive"]}
+chrono = "0.4"
 dptree = "0.2"
 once_cell = "1"
 regex = "1"
diff --git a/bot/src/main.rs b/bot/src/main.rs
index a8e6a56..75fbbf2 100644
--- a/bot/src/main.rs
+++ b/bot/src/main.rs
@@ -11,6 +11,7 @@ use eh2telegraph::{
 
 use clap::Parser;
 
+use once_cell::sync::OnceCell;
 use teloxide::{
     adaptors::DefaultParseMode,
     dispatching::update_listeners,
@@ -52,6 +53,8 @@ struct Args {
     config: Option<String>,
 }
 
+static PROCESS_MESSAGE_DATE: OnceCell<chrono::DateTime<chrono::Utc>> = OnceCell::new();
+
 #[tokio::main]
 async fn main() {
     let args = Args::parse();
@@ -59,6 +62,14 @@ async fn main() {
     let timer = tracing_subscriber::fmt::time::LocalTime::new(time::macros::format_description!(
         "[month]-[day] [hour]:[minute]:[second]"
     ));
+    // We will only process messages from 1 day earlier.
+    PROCESS_MESSAGE_DATE
+        .set(
+            chrono::Utc::now()
+                .checked_sub_signed(chrono::Duration::days(1))
+                .expect("illegal current date"),
+        )
+        .expect("unable to set global date");
     tracing_subscriber::fmt().with_timer(timer).init();
     tracing::info!("initializing...");
 
@@ -126,6 +137,16 @@ async fn main() {
             Some(message)
         }
     };
+    let time_filter = |message: Message| async move {
+        // Ignore old message.
+        // # Safety:
+        // We already set PROCESS_MESSAGE_DATE.
+        if &message.date > unsafe { PROCESS_MESSAGE_DATE.get_unchecked() } {
+            Some(message)
+        } else {
+            None
+        }
+    };
 
     let bot = Bot::new(base_config.bot_token)
         .parse_mode(ParseMode::MarkdownV2)
@@ -139,6 +160,7 @@ async fn main() {
                     _ => None,
                 }
             }))
+            .chain(dptree::filter_map_async(time_filter))
             .chain(dptree::filter_map_async(permission_filter))
             .branch(
                 dptree::entry()