diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fdad2bca566f..618fd2179491 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -60,10 +60,25 @@ jobs:
           if [[ -n '${{ secrets.PUSH_NIGHTLY_TOKEN }}' ]]; then
             git remote add nightly https://foo:'${{ secrets.PUSH_NIGHTLY_TOKEN }}'@github.com/${{ github.repository_owner }}/lean4-nightly.git
             git fetch nightly --tags
-            LEAN_VERSION_STRING="nightly-$(date -u +%F)"
-            # do nothing if commit already has a different tag
-            if [[ "$(git name-rev --name-only --tags --no-undefined HEAD 2> /dev/null || echo "$LEAN_VERSION_STRING")" == "$LEAN_VERSION_STRING" ]]; then
+            BASE_NIGHTLY="nightly-$(date -u +%F)"
+            if [[ '${{ github.event_name }}' == 'workflow_dispatch' ]]; then
+              # Manual re-release: find next available revision if base nightly exists
+              if git rev-parse "refs/tags/$BASE_NIGHTLY" >/dev/null 2>&1; then
+                REV=1
+                while git rev-parse "refs/tags/${BASE_NIGHTLY}-rev${REV}" >/dev/null 2>&1; do
+                  REV=$((REV + 1))
+                done
+                LEAN_VERSION_STRING="${BASE_NIGHTLY}-rev${REV}"
+              else
+                LEAN_VERSION_STRING="$BASE_NIGHTLY"
+              fi
               echo "nightly=$LEAN_VERSION_STRING" >> "$GITHUB_OUTPUT"
+            else
+              # Scheduled: do nothing if commit already has a different tag
+              LEAN_VERSION_STRING="$BASE_NIGHTLY"
+              if [[ "$(git name-rev --name-only --tags --no-undefined HEAD 2> /dev/null || echo "$LEAN_VERSION_STRING")" == "$LEAN_VERSION_STRING" ]]; then
+                echo "nightly=$LEAN_VERSION_STRING" >> "$GITHUB_OUTPUT"
+              fi
             fi
           fi
 
@@ -475,7 +490,7 @@ jobs:
           git tag "${{ needs.configure.outputs.nightly }}"
           git push nightly "${{ needs.configure.outputs.nightly }}"
           git push -f origin refs/tags/${{ needs.configure.outputs.nightly }}:refs/heads/nightly
-          last_tag="$(git log HEAD^ --simplify-by-decoration --pretty="format:%d" | grep -o "nightly-[-0-9]*" | head -n 1)"
+          last_tag="$(git log HEAD^ --simplify-by-decoration --pretty="format:%d" | grep -o "nightly-[^ ,)]*" | head -n 1)"
           echo -e "*Changes since ${last_tag}:*\n\n" > diff.md
           git show "$last_tag":RELEASES.md > old.md
           #./script/diff_changelogs.py old.md doc/changes.md >> diff.md
diff --git a/script/lean-bisect b/script/lean-bisect
index faaf4d7b5559..7ab7f93e943c 100755
--- a/script/lean-bisect
+++ b/script/lean-bisect
@@ -36,7 +36,7 @@ sys.path.insert(0, str(Path(__file__).parent))
 import build_artifact
 
 # Constants
-NIGHTLY_PATTERN = re.compile(r'^nightly-(\d{4})-(\d{2})-(\d{2})$')
+NIGHTLY_PATTERN = re.compile(r'^nightly-(\d{4})-(\d{2})-(\d{2})(-rev(\d+))?$')
 VERSION_PATTERN = re.compile(r'^v4\.(\d+)\.(\d+)(-rc\d+)?$')
 # Accept short SHAs (7+ chars) - we'll resolve to full SHA later
 SHA_PATTERN = re.compile(r'^[0-9a-f]{7,40}$')
@@ -158,7 +158,7 @@ def parse_identifier(s: str) -> Tuple[str, str]:
         return ('sha', full_sha)
     error(f"Invalid identifier format: '{s}'\n"
           f"Expected one of:\n"
-          f"  - nightly-YYYY-MM-DD (e.g., nightly-2024-06-15)\n"
+          f"  - nightly-YYYY-MM-DD or nightly-YYYY-MM-DD-revK (e.g., nightly-2024-06-15, nightly-2024-06-15-rev1)\n"
           f"  - v4.X.Y or v4.X.Y-rcK (e.g., v4.8.0, v4.9.0-rc1)\n"
           f"  - commit SHA (short or full)")
 
@@ -244,8 +244,13 @@ def fetch_nightly_tags() -> List[str]:
         if len(data) < 100:
             break
 
-    # Sort by date (nightly-YYYY-MM-DD format sorts lexicographically)
-    tags.sort()
+    # Sort by date and revision (nightly-YYYY-MM-DD-revK needs numeric comparison on rev)
+    def nightly_sort_key(tag):
+        m = NIGHTLY_PATTERN.match(tag)
+        if m:
+            return (int(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(5) or 0))
+        return (0, 0, 0, 0)
+    tags.sort(key=nightly_sort_key)
     return tags
 
 def get_commit_for_nightly(nightly: str) -> str:
@@ -1024,6 +1029,7 @@ Range Syntax:
 Identifier Formats:
 
   nightly-YYYY-MM-DD    Nightly build date (e.g., nightly-2024-06-15)
+  nightly-YYYY-MM-DD-revK  Revised nightly (e.g., nightly-2024-06-15-rev1)
                         Uses pre-built toolchains from leanprover/lean4-nightly.
                         Fast: downloads via elan (~30s each).
 
@@ -1151,9 +1157,9 @@ Examples:
     # Validate --nightly-only
     if args.nightly_only:
         if from_val is not None and from_type != 'nightly':
-            error("--nightly-only requires FROM to be a nightly identifier (nightly-YYYY-MM-DD)")
+            error("--nightly-only requires FROM to be a nightly identifier (nightly-YYYY-MM-DD or nightly-YYYY-MM-DD-revK)")
         if to_type != 'nightly':
-            error("--nightly-only requires TO to be a nightly identifier (nightly-YYYY-MM-DD)")
+            error("--nightly-only requires TO to be a nightly identifier (nightly-YYYY-MM-DD or nightly-YYYY-MM-DD-revK)")
 
     if from_val:
         info(f"From: {from_val} ({from_type})")
diff --git a/src/lake/Lake/Util/Version.lean b/src/lake/Lake/Util/Version.lean
index ff44901c29e5..8e5f6abbd0d0 100644
--- a/src/lake/Lake/Util/Version.lean
+++ b/src/lake/Lake/Util/Version.lean
@@ -235,13 +235,14 @@ open ToolchainVer in
 /-- A Lean toolchain version. -/
 inductive ToolchainVer
 | release (ver : LeanVer)
-| nightly (date : Date)
+| nightly (date : Date) (rev : Option Nat := none)
 | pr (n : Nat)
 | other (v : String)
 with
   @[computed_field] toString : ToolchainVer → String
     | .release ver => s!"{defaultOrigin}:v{ver}"
-    | .nightly date => s!"{defaultOrigin}:nightly-{date}"
+    | .nightly date rev => s!"{defaultOrigin}:nightly-{date}" ++
+        match rev with | none => "" | some r => s!"-rev{r}"
     | .pr n => s!"{prOrigin}:pr-release-{n}"
     | .other v => v
 deriving Repr, DecidableEq
@@ -264,13 +265,20 @@ public def ofString (ver : String) : ToolchainVer := Id.run do
     if let .ok ver := StdVer.parse (tag.drop 1).copy then
       if noOrigin|| origin == defaultOrigin then
         return .release ver
-  else if let some date := tag.dropPrefix? "nightly-" then
-    if let some date := Date.ofString? date.toString then
-      if noOrigin then
-        return .nightly date
-      else if let some suffix := origin.dropPrefix? defaultOrigin then
-        if suffix.isEmpty || suffix == "-nightly" then
-          return .nightly date
+  else if let some rest := tag.dropPrefix? "nightly-" then
+    let rest := rest.toString
+    -- Dates are exactly 10 characters (YYYY-MM-DD); anything after must be a -revK suffix
+    if let some date := Date.ofString? (rest.take 10).toString then
+      let rev? : Option Nat := do
+        let suffix ← (rest.drop 10).dropPrefix? "-rev"
+        suffix.toString.toNat?
+      -- Accept if no suffix (plain nightly) or valid -revK suffix
+      if rest.length ≤ 10 || rev?.isSome then
+        if noOrigin then
+          return .nightly date rev?
+        else if let some suffix := origin.dropPrefix? defaultOrigin then
+          if suffix.isEmpty || suffix == "-nightly" then
+            return .nightly date rev?
   else if let some n := tag.dropPrefix?  "pr-release-" then
     if let some n := n.toNat? then
       if noOrigin || origin == prOrigin then
@@ -301,7 +309,8 @@ public instance : FromJson ToolchainVer := ⟨(ToolchainVer.ofString <$> fromJso
 public def blt (a b : ToolchainVer) : Bool :=
   match a, b with
   | .release v1, .release v2 => v1 < v2
-  | .nightly d1, .nightly d2 => d1 < d2
+  | .nightly d1 r1, .nightly d2 r2 =>
+    d1 < d2 || (d1 == d2 && (r1.getD 0) < (r2.getD 0))
   | _, _ => false
 
 public instance : LT ToolchainVer := ⟨(·.blt ·)⟩
@@ -311,7 +320,8 @@ public instance decLt (a b : ToolchainVer) : Decidable (a < b) :=
 public def ble (a b : ToolchainVer) : Bool :=
   match a, b with
   | .release v1, .release v2 => v1 ≤ v2
-  | .nightly d1, .nightly d2 => d1 ≤ d2
+  | .nightly d1 r1, .nightly d2 r2 =>
+    d1 < d2 || (d1 == d2 && (r1.getD 0) ≤ (r2.getD 0))
   | .pr n1, .pr n2 => n1 = n2
   | .other v1, .other v2 => v1 = v2
   | _, _ => false
diff --git a/tests/lake/tests/updateToolchain/test.lean b/tests/lake/tests/updateToolchain/test.lean
index c15208018283..d369e585acc9 100644
--- a/tests/lake/tests/updateToolchain/test.lean
+++ b/tests/lake/tests/updateToolchain/test.lean
@@ -12,21 +12,33 @@ def test := do
   IO.println ""
   checkParse "leanprover/lean4:v4.13.0-rc1"
   checkParse "leanprover/lean4:nightly-2024-09-15"
+  checkParse "leanprover/lean4:nightly-2024-09-15-rev1"
+  checkParse "nightly-2024-09-15-rev2"
   checkParse "leanprover/lean4-pr-releases:pr-release-101"
   checkParse "leanprover/lean:v4.1.0"
   checkParse "4.12.0"
+  checkParse "nightly-2024-09-15-foo"  -- malformed suffix → .other
   checkLt "4.6.0-rc1" "v4.6.0"
   checkLt "4.12.0" "leanprover/lean4:v4.13.0-rc1"
   checkLt "nightly-2024-09-08" "nightly-2024-10-09"
+  checkLt "nightly-2024-09-08" "nightly-2024-09-08-rev1"
+  checkLt "nightly-2024-09-08-rev1" "nightly-2024-09-08-rev2"
+  checkLt "nightly-2024-09-08-rev2" "nightly-2024-09-09"
   checkLt "nightly-2024-09-08" "4.0.0"
 
 /--
 info:
 Lake.ToolchainVer.release { toSemVerCore := { major := 4, minor := 13, patch := 0 }, specialDescr := "rc1" }
-Lake.ToolchainVer.nightly { year := 2024, month := 9, day := 15 }
+Lake.ToolchainVer.nightly { year := 2024, month := 9, day := 15 } none
+Lake.ToolchainVer.nightly { year := 2024, month := 9, day := 15 } (some 1)
+Lake.ToolchainVer.nightly { year := 2024, month := 9, day := 15 } (some 2)
 Lake.ToolchainVer.pr 101
 Lake.ToolchainVer.other "leanprover/lean:v4.1.0"
 Lake.ToolchainVer.release { toSemVerCore := { major := 4, minor := 12, patch := 0 }, specialDescr := "" }
+Lake.ToolchainVer.other "nightly-2024-09-15-foo"
+true
+true
+true
 true
 true
 true
diff --git a/tests/lake/tests/updateToolchain/test.sh b/tests/lake/tests/updateToolchain/test.sh
index aa688ea305ec..8cec228823e4 100755
--- a/tests/lake/tests/updateToolchain/test.sh
+++ b/tests/lake/tests/updateToolchain/test.sh
@@ -42,6 +42,12 @@ echo nightly-2024-10-01 > a/lean-toolchain
 echo nightly-2024-01-10 > b/lean-toolchain
 test_update leanprover/lean4:nightly-2024-10-01
 
+# Test nightly revision comparison
+./clean.sh
+echo nightly-2024-10-01-rev1 > a/lean-toolchain
+echo nightly-2024-01-10 > b/lean-toolchain
+test_update leanprover/lean4:nightly-2024-10-01-rev1
+
 # Test up-to-date root
 ./clean.sh
 echo v4.4.0 > a/lean-toolchain