diff --git a/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Run.hs b/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Run.hs
index 2832ffd437..f5dcb402e3 100644
--- a/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Run.hs
+++ b/ouroboros-consensus-cardano/src/unstable-cardano-tools/Cardano/Tools/DBAnalyser/Run.hs
@@ -75,6 +75,7 @@ openLedgerDB lgrDbArgs@LedgerDB.LedgerDbArgs{LedgerDB.lgrFlavorArgs = LedgerDB.L
           bss
           (\_ -> error "no replay")
           snapManager
+          (LedgerDB.praosGetVolatileSuffix $ LedgerDB.ledgerDbCfgSecParam $ LedgerDB.lgrConfig lgrDbArgs)
       )
       snapManager
       emptyStream
@@ -92,6 +93,7 @@ openLedgerDB lgrDbArgs@LedgerDB.LedgerDbArgs{LedgerDB.lgrFlavorArgs = LedgerDB.L
           bss'
           (\_ -> error "no replay")
           snapManager
+          (LedgerDB.praosGetVolatileSuffix $ LedgerDB.ledgerDbCfgSecParam $ LedgerDB.lgrConfig lgrDbArgs)
       )
       snapManager
       emptyStream
diff --git a/ouroboros-consensus-diffusion/test/consensus-test/Test/Consensus/PeerSimulator/Trace.hs b/ouroboros-consensus-diffusion/test/consensus-test/Test/Consensus/PeerSimulator/Trace.hs
index feda424c51..d7acdf1fdc 100644
--- a/ouroboros-consensus-diffusion/test/consensus-test/Test/Consensus/PeerSimulator/Trace.hs
+++ b/ouroboros-consensus-diffusion/test/consensus-test/Test/Consensus/PeerSimulator/Trace.hs
@@ -418,8 +418,8 @@ traceChainDBEventTestBlockWith tracer = \case
         trace $ "Switched to a fork; now: " ++ terseHFragment newFragment
       StoreButDontChange point ->
         trace $ "Did not select block due to LoE: " ++ terseRealPoint point
-      IgnoreBlockOlderThanK point ->
-        trace $ "Ignored block older than k: " ++ terseRealPoint point
+      IgnoreBlockOlderThanImmTip point ->
+        trace $ "Ignored block older than imm tip: " ++ terseRealPoint point
       ChainSelectionLoEDebug curChain (LoEEnabled loeFrag0) -> do
         trace $ "Current chain: " ++ terseHFragment curChain
         trace $ "LoE fragment: " ++ terseHFragment loeFrag0
diff --git a/ouroboros-consensus/changelog.d/20250811_130239_alexander.esgen_decouple_immutability.md b/ouroboros-consensus/changelog.d/20250811_130239_alexander.esgen_decouple_immutability.md
new file mode 100644
index 0000000000..43ecf32dcd
--- /dev/null
+++ b/ouroboros-consensus/changelog.d/20250811_130239_alexander.esgen_decouple_immutability.md
@@ -0,0 +1,4 @@
+### Breaking
+
+- Renamed `IgnoreBlockOlderThanK` to `IgnoreBlockOlderThanImmTip` for future-proofing.
+- Renamed and simplified `olderThanK` to `olderThanImmTip`.
diff --git a/ouroboros-consensus/changelog.d/20250811_150947_alexander.esgen_decouple_immutability.md b/ouroboros-consensus/changelog.d/20250811_150947_alexander.esgen_decouple_immutability.md
new file mode 100644
index 0000000000..c48e80ce56
--- /dev/null
+++ b/ouroboros-consensus/changelog.d/20250811_150947_alexander.esgen_decouple_immutability.md
@@ -0,0 +1,7 @@
+### Breaking
+
+- LedgerDB: generalized over the criterion used to determine which states are
+  volatile/immutable, in preparation for Ouroboros Peras.
+
+  Concretely, `LedgerDB.openDB` takes a new argument, `GetVolatileSuffix m blk`.
+  For Praos behavior, use `praosGetVolatileSuffix`.
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/MiniProtocol/ChainSync/Client.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/MiniProtocol/ChainSync/Client.hs
index c5b3602353..ec16c91eca 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/MiniProtocol/ChainSync/Client.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/MiniProtocol/ChainSync/Client.hs
@@ -690,12 +690,10 @@ checkKnownIntersectionInvariants ::
   ( HasHeader blk
   , HasHeader (Header blk)
   , HasAnnTip blk
-  , ConsensusProtocol (BlockProtocol blk)
   ) =>
-  ConsensusConfig (BlockProtocol blk) ->
   KnownIntersectionState blk ->
   Either String ()
-checkKnownIntersectionInvariants cfg kis
+checkKnownIntersectionInvariants kis
   -- 'theirHeaderStateHistory' invariant
   | let HeaderStateHistory snapshots = theirHeaderStateHistory
         historyTips :: [WithOrigin (AnnTip blk)]
@@ -722,19 +720,6 @@ checkKnownIntersectionInvariants cfg kis
           , show fragmentAnchorPoint
           ]
   -- 'ourFrag' invariants
-  | let nbHeaders = AF.length ourFrag
-        ourAnchorPoint = AF.anchorPoint ourFrag
-  , nbHeaders < fromIntegral (unNonZero k)
-  , ourAnchorPoint /= GenesisPoint =
-      throwError $
-        unwords
-          [ "ourFrag contains fewer than k headers and not close to genesis:"
-          , show nbHeaders
-          , "vs"
-          , show k
-          , "with anchor"
-          , show ourAnchorPoint
-          ]
   | let ourFragAnchor = AF.anchorPoint ourFrag
         theirFragAnchor = AF.anchorPoint theirFrag
   , ourFragAnchor /= castPoint theirFragAnchor =
@@ -760,8 +745,6 @@ checkKnownIntersectionInvariants cfg kis
   | otherwise =
       return ()
  where
-  SecurityParam k = protocolSecurityParam cfg
-
   KnownIntersectionState
     { mostRecentIntersection
     , ourFrag
@@ -773,14 +756,12 @@ assertKnownIntersectionInvariants ::
   ( HasHeader blk
   , HasHeader (Header blk)
   , HasAnnTip blk
-  , ConsensusProtocol (BlockProtocol blk)
   , HasCallStack
   ) =>
-  ConsensusConfig (BlockProtocol blk) ->
   KnownIntersectionState blk ->
   KnownIntersectionState blk
-assertKnownIntersectionInvariants cfg kis =
-  assertWithMsg (checkKnownIntersectionInvariants cfg kis) kis
+assertKnownIntersectionInvariants kis =
+  assertWithMsg (checkKnownIntersectionInvariants kis) kis
 
 {-------------------------------------------------------------------------------
   The ChainSync client definition
@@ -891,8 +872,7 @@ chainSyncClient cfgEnv dynEnv =
             (ForkTooDeep GenesisPoint)
  where
   ConfigEnv
-    { cfg
-    , chainDbView
+    { chainDbView
     , tracer
     } = cfgEnv
 
@@ -994,7 +974,7 @@ chainSyncClient cfgEnv dynEnv =
                   -- we will /never/ adopt them, which is handled in the "no
                   -- more intersection case".
                   StillIntersects () $
-                    assertKnownIntersectionInvariants (configConsensus cfg) $
+                    assertKnownIntersectionInvariants $
                       KnownIntersectionState
                         { mostRecentIntersection = castPoint intersection
                         , ourFrag = ourFrag'
@@ -1157,7 +1137,7 @@ findIntersectionTop cfgEnv dynEnv intEnv =
                 (ourTipFromChain ourFrag)
                 theirTip
       let kis =
-            assertKnownIntersectionInvariants (configConsensus cfg) $
+            assertKnownIntersectionInvariants $
               KnownIntersectionState
                 { mostRecentIntersection = intersection
                 , ourFrag
@@ -1233,7 +1213,6 @@ knownIntersectionStateTop cfgEnv dynEnv intEnv =
   ConfigEnv
     { mkPipelineDecision0
     , tracer
-    , cfg
     , historicityCheck
     } = cfgEnv
 
@@ -1621,9 +1600,8 @@ knownIntersectionStateTop cfgEnv dynEnv intEnv =
                         else mostRecentIntersection
 
                     kis' =
-                      assertKnownIntersectionInvariants
-                        (configConsensus cfg)
-                        $ KnownIntersectionState
+                      assertKnownIntersectionInvariants $
+                        KnownIntersectionState
                           { mostRecentIntersection = mostRecentIntersection'
                           , ourFrag = ourFrag
                           , theirFrag = theirFrag'
@@ -1960,7 +1938,7 @@ checkValid cfgEnv intEnv hdr hdrSlotTime theirTip kis ledgerView = do
   traceWith (tracer cfgEnv) $ TraceValidatedHeader hdr
 
   pure $
-    assertKnownIntersectionInvariants (configConsensus cfg) $
+    assertKnownIntersectionInvariants $
       KnownIntersectionState
         { mostRecentIntersection = mostRecentIntersection'
         , ourFrag = ourFrag
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl.hs
index 3ee8da303f..e5f7b21014 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl.hs
@@ -53,6 +53,7 @@ import Data.Functor.Contravariant ((>$<))
 import qualified Data.Map.Strict as Map
 import Data.Maybe.Strict (StrictMaybe (..))
 import GHC.Stack (HasCallStack)
+import NoThunks.Class
 import Ouroboros.Consensus.Block
 import Ouroboros.Consensus.Config
 import qualified Ouroboros.Consensus.Fragment.Validated as VF
@@ -86,6 +87,7 @@ import Ouroboros.Consensus.Util.STM
   ( Fingerprint (..)
   , WithFingerprint (..)
   )
+import Ouroboros.Network.AnchoredFragment (AnchoredFragment)
 import qualified Ouroboros.Network.AnchoredFragment as AF
 import Ouroboros.Network.BlockFetch.ConsensusInterface
   ( ChainSelStarvation (..)
@@ -160,12 +162,15 @@ openDBInternal args launchBgTasks = runWithTempRegistry $ do
   (chainDB, testing, env) <- lift $ do
     traceWith tracer $ TraceOpenEvent (OpenedVolatileDB maxSlot)
     traceWith tracer $ TraceOpenEvent StartedOpeningLgrDB
+    (ledgerDbGetVolatileSuffix, setGetCurrentChainForLedgerDB) <-
+      mkLedgerDbGetVolatileSuffix
     (lgrDB, replayed) <-
       LedgerDB.openDB
         argsLgrDb
         (ImmutableDB.streamAPI immutableDB)
         immutableDbTipPoint
         (Query.getAnyKnownBlock immutableDB volatileDB)
+        ledgerDbGetVolatileSuffix
     traceWith tracer $ TraceOpenEvent OpenedLgrDB
 
     varInvalid <- newTVarIO (WithFingerprint Map.empty (Fingerprint 0))
@@ -246,6 +251,9 @@ openDBInternal args launchBgTasks = runWithTempRegistry $ do
             , cdbLoE = Args.cdbsLoE cdbSpecificArgs
             , cdbChainSelStarvation = varChainSelStarvation
             }
+
+    setGetCurrentChainForLedgerDB $ Query.getCurrentChain env
+
     h <- fmap CDBHandle $ newTVarIO $ ChainDbOpen env
     let chainDB =
           API.ChainDB
@@ -304,6 +312,38 @@ openDBInternal args launchBgTasks = runWithTempRegistry $ do
   tracer = Args.cdbsTracer cdbSpecificArgs
   Args.ChainDbArgs argsImmutableDb argsVolatileDb argsLgrDb cdbSpecificArgs = args
 
+  -- The LedgerDB requires a criterion ('LedgerDB.GetVolatileSuffix')
+  -- determining which of its states are volatile/immutable. Once we have
+  -- initialized the ChainDB we can defer this decision to
+  -- 'Query.getCurrentChain'.
+  --
+  -- However, we initialize the LedgerDB before the ChainDB (for initial chain
+  -- selection), so during that period, we temporarily consider no state (apart
+  -- from the anchor state) as immutable. This is fine as we don't perform eg
+  -- any rollbacks during this period.
+  mkLedgerDbGetVolatileSuffix ::
+    m
+      ( LedgerDB.GetVolatileSuffix m blk
+      , STM m (AnchoredFragment (Header blk)) -> m ()
+      )
+  mkLedgerDbGetVolatileSuffix = do
+    varGetCurrentChain ::
+      StrictTMVar m (OnlyCheckWhnf (STM m (AnchoredFragment (Header blk)))) <-
+      newEmptyTMVarIO
+    let getVolatileSuffix =
+          LedgerDB.GetVolatileSuffix $
+            tryReadTMVar varGetCurrentChain >>= \case
+              -- If @setVarChain@ has not yet been invoked, return the entire
+              -- suffix as volatile.
+              Nothing -> pure id
+              -- Otherwise, return the suffix with the same length as the
+              -- current chain.
+              Just (OnlyCheckWhnf getCurrentChain) -> do
+                curChainLen <- AF.length <$> getCurrentChain
+                pure $ AF.anchorNewest (fromIntegral curChainLen)
+        setVarChain = atomically . writeTMVar varGetCurrentChain . OnlyCheckWhnf
+    pure (getVolatileSuffix, setVarChain)
+
 -- | We use 'runInnerWithTempRegistry' for the component databases.
 innerOpenCont ::
   IOLike m =>
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Background.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Background.hs
index ed8ce9bc97..37cfd65e27 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Background.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Background.hs
@@ -41,7 +41,6 @@ module Ouroboros.Consensus.Storage.ChainDB.Impl.Background
   , addBlockRunner
   ) where
 
-import Cardano.Ledger.BaseTypes (unNonZero)
 import Control.Exception (assert)
 import Control.Monad (forM_, forever, void)
 import Control.Monad.Trans.Class (lift)
@@ -57,7 +56,6 @@ import Data.Word
 import GHC.Generics (Generic)
 import GHC.Stack (HasCallStack)
 import Ouroboros.Consensus.Block
-import Ouroboros.Consensus.Config
 import Ouroboros.Consensus.HardFork.Abstract
 import Ouroboros.Consensus.Ledger.Inspect
 import Ouroboros.Consensus.Ledger.SupportsProtocol
@@ -69,6 +67,7 @@ import Ouroboros.Consensus.Storage.ChainDB.API
 import Ouroboros.Consensus.Storage.ChainDB.Impl.ChainSel
   ( chainSelSync
   )
+import qualified Ouroboros.Consensus.Storage.ChainDB.Impl.Query as Query
 import Ouroboros.Consensus.Storage.ChainDB.Impl.Types
 import qualified Ouroboros.Consensus.Storage.ImmutableDB as ImmutableDB
 import qualified Ouroboros.Consensus.Storage.LedgerDB as LedgerDB
@@ -132,10 +131,11 @@ launchBgTasks cdb@CDB{..} replayed = do
   Copying blocks from the VolatileDB to the ImmutableDB
 -------------------------------------------------------------------------------}
 
--- | Copy the blocks older than @k@ from the VolatileDB to the ImmutableDB.
+-- | Copy the blocks older than the immutable tip from the VolatileDB to the
+-- ImmutableDB.
 --
--- These headers of these blocks can be retrieved by dropping the @k@ most
--- recent blocks from the fragment stored in 'cdbChain'.
+-- The headers of these blocks can be retrieved by considering headers in
+-- 'cdbChain' that are not also in 'getCurrentChain' (a suffix of 'cdbChain').
 --
 -- The copied blocks are removed from the fragment stored in 'cdbChain'.
 --
@@ -153,10 +153,11 @@ copyToImmutableDB ::
   ) =>
   ChainDbEnv m blk ->
   Electric m (WithOrigin SlotNo)
-copyToImmutableDB CDB{..} = electric $ do
+copyToImmutableDB cdb@CDB{..} = electric $ do
   toCopy <- atomically $ do
     curChain <- icWithoutTime <$> readTVar cdbChain
-    let nbToCopy = max 0 (AF.length curChain - fromIntegral (unNonZero k))
+    curChainVolSuffix <- Query.getCurrentChain cdb
+    let nbToCopy = max 0 $ AF.length curChain - AF.length curChainVolSuffix
         toCopy :: [Point blk]
         toCopy =
           map headerPoint $
@@ -165,10 +166,10 @@ copyToImmutableDB CDB{..} = electric $ do
     return toCopy
 
   if null toCopy
-    -- This can't happen in practice, as we're only called when the fragment
-    -- is longer than @k@. However, in the tests, we will be calling this
-    -- function manually, which means it might be called when there are no
-    -- blocks to copy.
+    -- This can't happen in practice, as we're only called when there are new
+    -- immutable blocks. However, in the tests, we will be calling this function
+    -- manually, which means it might be called when there are no blocks to
+    -- copy.
     then trace NoBlocksToCopyToImmutableDB
     else forM_ toCopy $ \pt -> do
       let hash = case pointHash pt of
@@ -193,7 +194,6 @@ copyToImmutableDB CDB{..} = electric $ do
   -- Get the /possibly/ updated tip of the ImmutableDB
   atomically $ ImmutableDB.getTipSlot cdbImmutableDB
  where
-  SecurityParam k = configSecurityParam cdbTopLevelConfig
   trace = traceWith (contramap TraceCopyToImmutableDBEvent cdbTracer)
 
   -- \| Remove the header corresponding to the given point from the beginning
@@ -218,9 +218,11 @@ copyToImmutableDB CDB{..} = electric $ do
 -- | Copy blocks from the VolatileDB to ImmutableDB and trigger further tasks in
 -- other threads.
 --
--- We watch the chain for changes. Whenever the chain is longer than @k@, then
--- the headers older than @k@ are copied from the VolatileDB to the ImmutableDB
--- (using 'copyToImmutableDB'). Once that is complete,
+-- Wait until the current chain ('cdbChain') is longer than its volatile suffix
+-- ('getCurrentChain'). When this occurs, it indicates that new blocks have
+-- become immutable. These newly immutable blocks are then copied from the
+-- VolatileDB to the ImmutableDB (using 'copyToImmutableDB'). Once that is
+-- complete,
 --
 -- * Trigger LedgerDB maintenance tasks, namely flushing, taking snapshots and
 --   garbage collection.
@@ -254,15 +256,15 @@ copyToImmutableDBRunner cdb@CDB{..} ledgerDbTasksTrigger gcSchedule fuse = do
   LedgerDB.tryFlush cdbLedgerDB
   forever copyAndTrigger
  where
-  SecurityParam k = configSecurityParam cdbTopLevelConfig
-
   copyAndTrigger :: m ()
   copyAndTrigger = do
-    -- Wait for the chain to grow larger than @k@
+    -- Wait for 'cdbChain' to become longer than 'getCurrentChain'.
     numToWrite <- atomically $ do
       curChain <- icWithoutTime <$> readTVar cdbChain
-      check $ fromIntegral (AF.length curChain) > unNonZero k
-      return $ fromIntegral (AF.length curChain) - unNonZero k
+      curChainVolSuffix <- Query.getCurrentChain cdb
+      let numToWrite = AF.length curChain - AF.length curChainVolSuffix
+      check $ numToWrite > 0
+      return $ fromIntegral numToWrite
 
     -- Copy blocks to ImmutableDB
     --
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/ChainSel.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/ChainSel.hs
index 64abc21d14..a16e674b3d 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/ChainSel.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/ChainSel.hs
@@ -19,7 +19,7 @@ module Ouroboros.Consensus.Storage.ChainDB.Impl.ChainSel
   , triggerChainSelectionAsync
 
     -- * Exported for testing purposes
-  , olderThanK
+  , olderThanImmTip
   ) where
 
 import Cardano.Ledger.BaseTypes (unNonZero)
@@ -411,8 +411,8 @@ chainSelSync cdb@CDB{..} (ChainSelAddBlock BlockToAdd{blockToAdd = b, ..}) = do
   -- We follow the steps from section "## Adding a block" in ChainDB.md
 
   if
-    | olderThanK hdr isEBB immBlockNo -> do
-        lift $ traceWith addBlockTracer $ IgnoreBlockOlderThanK (blockRealPoint b)
+    | olderThanImmTip hdr immBlockNo -> do
+        lift $ traceWith addBlockTracer $ IgnoreBlockOlderThanImmTip (blockRealPoint b)
         lift $ deliverWrittenToDisk False
     | isMember (blockHash b) -> do
         lift $ traceWith addBlockTracer $ IgnoreBlockAlreadyInVolatileDB (blockRealPoint b)
@@ -466,31 +466,28 @@ chainSelSync cdb@CDB{..} (ChainSelAddBlock BlockToAdd{blockToAdd = b, ..}) = do
 
 -- | Return 'True' when the given header should be ignored when adding it
 -- because it is too old, i.e., we wouldn't be able to switch to a chain
--- containing the corresponding block because its block number is more than
--- @k@ blocks or exactly @k@ blocks back.
+-- containing the corresponding block because its block number is (weakly) older
+-- than that of the immutable tip.
 --
 -- Special case: the header corresponds to an EBB which has the same block
--- number as the block @k@ blocks back (the most recent \"immutable\" block).
--- As EBBs share their block number with the block before them, the EBB is not
--- too old in that case and can be adopted as part of our chain.
+-- number as the most recent \"immutable\" block. As EBBs share their block
+-- number with the block before them, the EBB is not too old in that case and
+-- can be adopted as part of our chain.
 --
 -- This special case can occur, for example, when the VolatileDB is empty
 -- (because of corruption). The \"immutable\" block is then also the tip of
 -- the chain. If we then try to add the EBB after it, it will have the same
 -- block number, so we must allow it.
-olderThanK ::
-  HasHeader (Header blk) =>
+olderThanImmTip ::
+  GetHeader blk =>
   -- | Header of the block to add
   Header blk ->
-  -- | Whether the block is an EBB or not
-  IsEBB ->
-  -- | The block number of the most recent \"immutable\" block, i.e., the
-  -- block @k@ blocks back.
+  -- | The block number of the most recent immutable block.
   WithOrigin BlockNo ->
   Bool
-olderThanK hdr isEBB immBlockNo
+olderThanImmTip hdr immBlockNo
   | NotOrigin bNo == immBlockNo
-  , isEBB == IsEBB =
+  , headerToIsEBB hdr == IsEBB =
       False
   | otherwise =
       NotOrigin bNo <= immBlockNo
@@ -559,9 +556,9 @@ chainSelectionForBlock cdb@CDB{..} blockCache hdr punish = electric $ withRegist
 
   if
     -- The chain might have grown since we added the block such that the
-    -- block is older than @k@.
-    | olderThanK hdr isEBB immBlockNo -> do
-        traceWith addBlockTracer $ IgnoreBlockOlderThanK p
+    -- block is older than the immutable tip.
+    | olderThanImmTip hdr immBlockNo -> do
+        traceWith addBlockTracer $ IgnoreBlockOlderThanImmTip p
 
     -- The block is invalid
     | Just (InvalidBlockInfo reason _) <- Map.lookup (headerHash hdr) invalid -> do
@@ -609,9 +606,6 @@ chainSelectionForBlock cdb@CDB{..} blockCache hdr punish = electric $ withRegist
   p :: RealPoint blk
   p = headerRealPoint hdr
 
-  isEBB :: IsEBB
-  isEBB = headerToIsEBB hdr
-
   addBlockTracer :: Tracer m (TraceAddBlockEvent blk)
   addBlockTracer = TraceAddBlockEvent >$< cdbTracer
 
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Types.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Types.hs
index 61a3c7380d..30193ba314 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Types.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/ChainDB/Impl/Types.hs
@@ -815,9 +815,8 @@ deriving stock instance
 
 -- | Trace type for the various events that occur when adding a block.
 data TraceAddBlockEvent blk
-  = -- | A block with a 'BlockNo' more than @k@ back than the current tip was
-    -- ignored.
-    IgnoreBlockOlderThanK (RealPoint blk)
+  = -- | A block with a 'BlockNo' not newer than the immutable tip was ignored.
+    IgnoreBlockOlderThanImmTip (RealPoint blk)
   | -- | A block that is already in the Volatile DB was ignored.
     IgnoreBlockAlreadyInVolatileDB (RealPoint blk)
   | -- | A block that is know to be invalid was ignored.
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB.hs
index 4b03b5e22d..0d1380d505 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB.hs
@@ -62,12 +62,14 @@ openDB ::
   Point blk ->
   -- | How to get blocks from the ChainDB
   ResolveBlock m blk ->
+  GetVolatileSuffix m blk ->
   m (LedgerDB' m blk, Word64)
 openDB
   args
   stream
   replayGoal
-  getBlock = case lgrFlavorArgs args of
+  getBlock
+  getVolatileSuffix = case lgrFlavorArgs args of
     LedgerDbFlavorArgsV1 bss ->
       let snapManager = V1.snapshotManager args
           initDb =
@@ -76,6 +78,7 @@ openDB
               bss
               getBlock
               snapManager
+              getVolatileSuffix
        in doOpenDB args initDb snapManager stream replayGoal
     LedgerDbFlavorArgsV2 bss -> do
       (snapManager, bss') <- case bss of
@@ -87,6 +90,7 @@ openDB
               bss'
               getBlock
               snapManager
+              getVolatileSuffix
       doOpenDB args initDb snapManager stream replayGoal
 
 {-------------------------------------------------------------------------------
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/Args.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/Args.hs
index 63935c89fa..fa3835306a 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/Args.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/Args.hs
@@ -2,7 +2,7 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveAnyClass #-}
 {-# LANGUAGE DeriveGeneric #-}
-{-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE DerivingVia #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GADTs #-}
@@ -22,14 +22,21 @@ module Ouroboros.Consensus.Storage.LedgerDB.Args
   , QueryBatchSize (..)
   , defaultArgs
   , defaultQueryBatchSize
+
+    -- * 'GetVolatileSuffix'
+  , GetVolatileSuffix (..)
+  , praosGetVolatileSuffix
   ) where
 
+import Cardano.Ledger.BaseTypes (unNonZero)
 import Control.ResourceRegistry
 import Control.Tracer
 import Data.Kind
 import Data.Word
 import GHC.Generics (Generic)
 import NoThunks.Class
+import Ouroboros.Consensus.Block
+import Ouroboros.Consensus.Config.SecurityParam
 import Ouroboros.Consensus.Ledger.Abstract
 import Ouroboros.Consensus.Ledger.Extended
 import Ouroboros.Consensus.Storage.LedgerDB.API
@@ -38,6 +45,9 @@ import Ouroboros.Consensus.Storage.LedgerDB.TraceEvent
 import qualified Ouroboros.Consensus.Storage.LedgerDB.V1.Args as V1
 import qualified Ouroboros.Consensus.Storage.LedgerDB.V2.Args as V2
 import Ouroboros.Consensus.Util.Args
+import Ouroboros.Consensus.Util.IOLike
+import Ouroboros.Network.AnchoredSeq (AnchoredSeq)
+import qualified Ouroboros.Network.AnchoredSeq as AS
 import System.FS.API
 
 {-------------------------------------------------------------------------------
@@ -120,3 +130,28 @@ defaultQueryBatchSize requestedQueryBatchSize = case requestedQueryBatchSize of
   -- acceptable performance. We might want to tweak this further, but for now
   -- this default seems good enough.
   DefaultQueryBatchSize -> 100_000
+
+{-------------------------------------------------------------------------------
+  GetVolatileSuffix
+-------------------------------------------------------------------------------}
+
+-- | Get the volatile suffix of the given 'AnchoredSeq' of states that the
+-- LedgerDB maintains.
+newtype GetVolatileSuffix m blk = GetVolatileSuffix
+  { getVolatileSuffix ::
+      forall s.
+      AS.Anchorable (WithOrigin SlotNo) s s =>
+      STM
+        m
+        ( AnchoredSeq (WithOrigin SlotNo) s s ->
+          AnchoredSeq (WithOrigin SlotNo) s s
+        )
+  }
+  deriving NoThunks via OnlyCheckWhnfNamed "GetVolatileSuffix" (GetVolatileSuffix m blk)
+
+-- | Return the the most recent @k@ blocks, which is the rule mandated by Praos.
+praosGetVolatileSuffix :: IOLike m => SecurityParam -> GetVolatileSuffix m blk
+praosGetVolatileSuffix secParam =
+  GetVolatileSuffix $ pure $ AS.anchorNewest k
+ where
+  k = unNonZero $ maxRollbacks secParam
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V1.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V1.hs
index c66f4152e3..13a9847273 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V1.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V1.hs
@@ -19,7 +19,6 @@
 -- module will be gone.
 module Ouroboros.Consensus.Storage.LedgerDB.V1 (mkInitDb) where
 
-import Cardano.Ledger.BaseTypes.NonZero (NonZero (..))
 import Control.Arrow ((>>>))
 import Control.Monad
 import Control.Monad.Except
@@ -87,8 +86,9 @@ mkInitDb ::
   Complete V1.LedgerDbFlavorArgs m ->
   ResolveBlock m blk ->
   SnapshotManagerV1 m blk ->
+  GetVolatileSuffix m blk ->
   InitDB (DbChangelog' blk, ResourceKey m, BackingStore' m blk) m blk
-mkInitDb args bss getBlock snapManager =
+mkInitDb args bss getBlock snapManager getVolatileSuffix =
   InitDB
     { initFromGenesis = do
         st <- lgrGenesis
@@ -146,6 +146,7 @@ mkInitDb args bss getBlock snapManager =
                 , ldbShouldFlush = shouldFlush flushFreq
                 , ldbQueryBatchSize = lgrQueryBatchSize
                 , ldbResolveBlock = getBlock
+                , ldbGetVolatileSuffix = getVolatileSuffix
                 }
         h <- LDBHandle <$> newTVarIO (LedgerDBOpen env)
         pure $ implMkLedgerDb h snapManager
@@ -208,10 +209,11 @@ implGetImmutableTip ::
   (MonadSTM m, GetTip l) =>
   LedgerDBEnv m l blk ->
   STM m (l EmptyMK)
-implGetImmutableTip env =
+implGetImmutableTip env = do
+  volSuffix <- getVolatileSuffix $ ldbGetVolatileSuffix env
   -- The DbChangelog might contain more than k states if they have not yet
   -- been garbage-collected.
-  fmap (AS.anchor . AS.anchorNewest (envMaxRollbacks env) . changelogStates)
+  fmap (AS.anchor . volSuffix . changelogStates)
     . readTVar
     $ ldbChangelog env
 
@@ -224,7 +226,8 @@ implGetPastLedgerState ::
   , HeaderHash l ~ HeaderHash blk
   ) =>
   LedgerDBEnv m l blk -> Point blk -> STM m (Maybe (l EmptyMK))
-implGetPastLedgerState env point =
+implGetPastLedgerState env point = do
+  volSuffix <- getVolatileSuffix $ ldbGetVolatileSuffix env
   readTVar (ldbChangelog env) <&> \chlog -> do
     -- The DbChangelog might contain more than k states if they have not yet
     -- been garbage-collected, so make sure that the point is volatile (or the
@@ -233,7 +236,7 @@ implGetPastLedgerState env point =
       AS.withinBounds
         (pointSlot point)
         ((point ==) . castPoint . either getTip getTip)
-        (AS.anchorNewest (envMaxRollbacks env) (changelogStates chlog))
+        (volSuffix (changelogStates chlog))
     getPastLedgerAt point chlog
 
 implGetHeaderStateHistory ::
@@ -246,6 +249,7 @@ implGetHeaderStateHistory ::
   LedgerDBEnv m l blk -> STM m (HeaderStateHistory blk)
 implGetHeaderStateHistory env = do
   ldb <- readTVar (ldbChangelog env)
+  volSuffix <- getVolatileSuffix $ ldbGetVolatileSuffix env
   let currentLedgerState = ledgerState $ current ldb
       -- This summary can convert all tip slots of the ledger states in the
       -- @ledgerDb@ as these are not newer than the tip slot of the current
@@ -259,7 +263,7 @@ implGetHeaderStateHistory env = do
     . AS.bimap mkHeaderStateWithTime' mkHeaderStateWithTime'
     -- The DbChangelog might contain more than k states if they have not yet
     -- been garbage-collected, so only take the corresponding suffix.
-    . AS.anchorNewest (envMaxRollbacks env)
+    . volSuffix
     $ changelogStates ldb
 
 implValidate ::
@@ -575,6 +579,7 @@ data LedgerDBEnv m l blk = LedgerDBEnv
   -- frequency that was provided when opening the LedgerDB.
   , ldbQueryBatchSize :: !QueryBatchSize
   , ldbResolveBlock :: !(ResolveBlock m blk)
+  , ldbGetVolatileSuffix :: !(GetVolatileSuffix m blk)
   }
   deriving Generic
 
@@ -588,10 +593,6 @@ deriving instance
   ) =>
   NoThunks (LedgerDBEnv m l blk)
 
--- | Return the security parameter @k@. Convenience function.
-envMaxRollbacks :: LedgerDBEnv m l blk -> Word64
-envMaxRollbacks = unNonZero . maxRollbacks . ledgerDbCfgSecParam . ldbCfg
-
 -- | Check if the LedgerDB is open, if so, executing the given function on the
 -- 'LedgerDBEnv', otherwise, throw a 'CloseDBError'.
 getEnv ::
@@ -763,10 +764,16 @@ acquireAtTarget ::
   ReadLocked m (Either GetForkerError (DbChangelog l))
 acquireAtTarget ldbEnv target = readLocked $ runExceptT $ do
   dblog <- lift $ readTVarIO (ldbChangelog ldbEnv)
+  volSuffix <- lift $ atomically $ getVolatileSuffix $ ldbGetVolatileSuffix ldbEnv
   -- The DbChangelog might contain more than k states if they have not yet
   -- been garbage-collected.
-  let immTip :: Point blk
-      immTip = castPoint $ getTip $ AS.anchor $ AS.anchorNewest k $ changelogStates dblog
+  let volStates = volSuffix $ changelogStates dblog
+
+      immTip :: Point blk
+      immTip = castPoint $ getTip $ AS.anchor volStates
+
+      rollbackMax :: Word64
+      rollbackMax = fromIntegral $ AS.length volStates
 
       rollbackTo pt
         | pointSlot pt < pointSlot immTip = throwError $ PointTooOld Nothing
@@ -779,7 +786,6 @@ acquireAtTarget ldbEnv target = readLocked $ runExceptT $ do
     Right ImmutableTip -> rollbackTo immTip
     Right (SpecificPoint pt) -> rollbackTo pt
     Left n -> do
-      let rollbackMax = maxRollback dblog `min` k
       when (n > rollbackMax) $
         throwError $
           PointTooOld $
@@ -791,8 +797,6 @@ acquireAtTarget ldbEnv target = readLocked $ runExceptT $ do
       case rollbackN n dblog of
         Nothing -> error "unreachable"
         Just dblog' -> pure dblog'
- where
-  k = envMaxRollbacks ldbEnv
 
 {-------------------------------------------------------------------------------
   Make forkers from consistent views
diff --git a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V2.hs b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V2.hs
index ef6ba64882..b6c6f6b087 100644
--- a/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V2.hs
+++ b/ouroboros-consensus/src/ouroboros-consensus/Ouroboros/Consensus/Storage/LedgerDB/V2.hs
@@ -16,7 +16,6 @@
 
 module Ouroboros.Consensus.Storage.LedgerDB.V2 (mkInitDb) where
 
-import Cardano.Ledger.BaseTypes (unNonZero)
 import Control.Arrow ((>>>))
 import qualified Control.Monad as Monad (join, void)
 import Control.Monad.Except
@@ -80,8 +79,9 @@ mkInitDb ::
   HandleEnv m ->
   ResolveBlock m blk ->
   SnapshotManagerV2 m blk ->
+  GetVolatileSuffix m blk ->
   InitDB (LedgerSeq' m blk) m blk
-mkInitDb args bss getBlock snapManager =
+mkInitDb args bss getBlock snapManager getVolatileSuffix =
   InitDB
     { initFromGenesis = emptyF =<< lgrGenesis
     , initFromSnapshot =
@@ -116,6 +116,7 @@ mkInitDb args bss getBlock snapManager =
                 , ldbOpenHandlesLock = lock
                 , ldbResourceKeys = case bss of
                     InMemoryHandleEnv -> Nothing
+                , ldbGetVolatileSuffix = getVolatileSuffix
                 }
         h <- LDBHandle <$> newTVarIO (LedgerDBOpen env)
         pure $ implMkLedgerDb h snapManager
@@ -455,6 +456,7 @@ data LedgerDBEnv m l blk = LedgerDBEnv
   -- ^ Resource keys used in the LSM backend so that the closing function used
   -- in tests can release such resources. These are the resource keys for the
   -- LSM session and the resource key for the BlockIO interface.
+  , ldbGetVolatileSuffix :: !(GetVolatileSuffix m blk)
   }
   deriving Generic
 
@@ -559,15 +561,16 @@ getEnvSTM (LDBHandle varState) f =
   Acquiring consistent views
 -------------------------------------------------------------------------------}
 
--- | Take the suffix of the 'ldbSeq' containing the @k@ most recent states. The
--- 'LedgerSeq' can contain more than @k@ states if we adopted new blocks, but
--- garbage collection has not yet been run.
+-- | Take the suffix of the 'ldbSeq' containing the only the volatile states
+-- (and the first immutable state at the anchor). The 'LedgerSeq' can contain
+-- more than one immutable state if we adopted new blocks, but garbage
+-- collection has not yet been run.
 getVolatileLedgerSeq ::
-  (MonadSTM m, GetTip l) => LedgerDBEnv m l blk -> STM m (LedgerSeq m l)
-getVolatileLedgerSeq env =
-  LedgerSeq . AS.anchorNewest k . getLedgerSeq <$> readTVar (ldbSeq env)
- where
-  k = unNonZero $ maxRollbacks $ ledgerDbCfgSecParam $ ldbCfg env
+  (MonadSTM m, GetTip l) =>
+  LedgerDBEnv m l blk -> STM m (LedgerSeq m l)
+getVolatileLedgerSeq env = do
+  volSuffix <- getVolatileSuffix (ldbGetVolatileSuffix env)
+  LedgerSeq . volSuffix . getLedgerSeq <$> readTVar (ldbSeq env)
 
 -- | Get a 'StateRef' from the 'LedgerSeq' in the 'LedgerDBEnv', with the
 -- 'LedgerTablesHandle' having been duplicated (such that the original can be
diff --git a/ouroboros-consensus/test/consensus-test/Test/Consensus/MiniProtocol/LocalStateQuery/Server.hs b/ouroboros-consensus/test/consensus-test/Test/Consensus/MiniProtocol/LocalStateQuery/Server.hs
index 0ab66ab540..efafdc18aa 100644
--- a/ouroboros-consensus/test/consensus-test/Test/Consensus/MiniProtocol/LocalStateQuery/Server.hs
+++ b/ouroboros-consensus/test/consensus-test/Test/Consensus/MiniProtocol/LocalStateQuery/Server.hs
@@ -244,6 +244,7 @@ initLedgerDB s c = do
         streamAPI
         (Chain.headPoint c)
         (\rpt -> pure $ fromMaybe (error "impossible") $ Chain.findBlock ((rpt ==) . blockRealPoint) c)
+        (LedgerDB.praosGetVolatileSuffix s)
 
   result <-
     LedgerDB.validateFork
diff --git a/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/ChainDB/Model.hs b/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/ChainDB/Model.hs
index 3369265f5e..d8cbf1acb0 100644
--- a/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/ChainDB/Model.hs
+++ b/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/ChainDB/Model.hs
@@ -122,7 +122,7 @@ import Ouroboros.Consensus.Storage.ChainDB.API
   , UnknownRange (..)
   , validBounds
   )
-import Ouroboros.Consensus.Storage.ChainDB.Impl.ChainSel (olderThanK)
+import Ouroboros.Consensus.Storage.ChainDB.Impl.ChainSel (olderThanImmTip)
 import Ouroboros.Consensus.Storage.Common ()
 import Ouroboros.Consensus.Util (repeatedly)
 import qualified Ouroboros.Consensus.Util.AnchoredFragment as Fragment
@@ -415,7 +415,7 @@ addBlock cfg blk m
   ignoreBlock =
     -- If the block is as old as the tip of the ImmutableDB, i.e. older
     -- than @k@, we ignore it, as we can never switch to it.
-    olderThanK hdr (headerToIsEBB hdr) immBlockNo
+    olderThanImmTip hdr immBlockNo
       ||
       -- If it's an invalid block we've seen before, ignore it.
       Map.member (blockHash blk) (invalid m)
diff --git a/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/LedgerDB/StateMachine.hs b/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/LedgerDB/StateMachine.hs
index 786951c7ea..5ab41c0551 100644
--- a/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/LedgerDB/StateMachine.hs
+++ b/ouroboros-consensus/test/storage-test/Test/Ouroboros/Storage/LedgerDB/StateMachine.hs
@@ -516,6 +516,7 @@ openLedgerDB flavArgs env cfg fs = do
               bss
               getBlock
               snapManager
+              (praosGetVolatileSuffix $ ledgerDbCfgSecParam cfg)
        in openDBInternal args initDb snapManager stream replayGoal
     LedgerDbFlavorArgsV2 bss -> do
       (snapManager, bss') <- case bss of
@@ -527,6 +528,7 @@ openLedgerDB flavArgs env cfg fs = do
               bss'
               getBlock
               snapManager
+              (praosGetVolatileSuffix $ ledgerDbCfgSecParam cfg)
       openDBInternal args initDb snapManager stream replayGoal
   withRegistry $ \reg -> do
     vr <- validateFork ldb reg (const $ pure ()) BlockCache.empty 0 (map getHeader volBlocks)