diff --git a/src/ripple/app/ledger/Ledger.cpp b/src/ripple/app/ledger/Ledger.cpp
index 5448d56c7..c72537eaf 100644
--- a/src/ripple/app/ledger/Ledger.cpp
+++ b/src/ripple/app/ledger/Ledger.cpp
@@ -192,7 +192,7 @@ Ledger::Ledger (create_genesis_t, Config const& config)
     updateHash();
     setClosed();
     setAccepted();
-    setFees(config);
+    setup(config);
 }
 
 Ledger::Ledger (uint256 const& parentHash,
@@ -240,7 +240,7 @@ Ledger::Ledger (uint256 const& parentHash,
 
     txMap_->setImmutable ();
     stateMap_->setImmutable ();
-    setFees(config);
+    setup(config);
 }
 
 // Create a new ledger that's a snapshot of this one
@@ -296,7 +296,7 @@ Ledger::Ledger (void const* data,
 {
     SerialIter sit (data, size);
     setRaw (sit, hasPrefix);
-    // We can't set the fees until the stateMap is populated
+    // Can't set up until the stateMap is filled in
 }
 
 Ledger::Ledger (std::uint32_t ledgerSeq,
@@ -312,7 +312,7 @@ Ledger::Ledger (std::uint32_t ledgerSeq,
     info_.seq = ledgerSeq;
     info_.closeTime = closeTime;
     info_.closeTimeResolution = ledgerDefaultTimeResolution;
-    setFees(config);
+    setup(config);
 }
 
 //------------------------------------------------------------------------------
@@ -332,7 +332,7 @@ void Ledger::setImmutable ()
         txMap_->setImmutable ();
     if (stateMap_)
         stateMap_->setImmutable ();
-    setFees (getConfig ());
+    setup(getConfig ());
 }
 
 void Ledger::updateHash()
@@ -1066,7 +1066,7 @@ Ledger::rawTxInsert (uint256 const& key,
 }
 
 void
-Ledger::setFees (Config const& config)
+Ledger::setup (Config const& config)
 {
     fees_.base = config.FEE_DEFAULT;
     fees_.units = config.TRANSACTION_FEE_BASE;
@@ -1089,6 +1089,7 @@ Ledger::setFees (Config const& config)
         if (sle->getFieldIndex (sfReserveIncrement) != -1)
             fees_.increment = sle->getFieldU32 (sfReserveIncrement);
     }
+    rules_ = Rules(*this);
 }
 
 std::shared_ptr<SLE>
diff --git a/src/ripple/app/ledger/Ledger.h b/src/ripple/app/ledger/Ledger.h
index 182bd32d0..303d43b58 100644
--- a/src/ripple/app/ledger/Ledger.h
+++ b/src/ripple/app/ledger/Ledger.h
@@ -142,6 +142,12 @@ public:
         return fees_;
     }
 
+    Rules const&
+    rules() const override
+    {
+        return rules_;
+    }
+
     bool
     exists (Keylet const& k) const override;
 
@@ -379,7 +385,7 @@ private:
     bool saveValidatedLedger (bool current);
 
     void
-    setFees (Config const& config);
+    setup (Config const& config);
 
     std::shared_ptr<SLE>
     peek (Keylet const& k) const;
@@ -406,6 +412,7 @@ private:
     std::mutex mutable mutex_;
 
     Fees fees_;
+    Rules rules_;
     LedgerInfo info_;
 
     // Ripple cost of the reference transaction
diff --git a/src/ripple/app/ledger/OpenLedger.h b/src/ripple/app/ledger/OpenLedger.h
index bbb9ca052..37f92d398 100644
--- a/src/ripple/app/ledger/OpenLedger.h
+++ b/src/ripple/app/ledger/OpenLedger.h
@@ -143,14 +143,16 @@ public:
             The current view is atomically set to the
             new open view.
 
+        @param rules The rules for the open ledger
         @param ledger A new closed ledger
     */
     void
-    accept(std::shared_ptr<Ledger const> const& ledger,
-        OrderedTxs const& locals, bool retriesFirst,
-            OrderedTxs& retries, ApplyFlags flags,
-                IHashRouter& router,
-                    std::string const& suffix = "");
+    accept (Rules const& rules,
+        std::shared_ptr<Ledger const> const& ledger,
+            OrderedTxs const& locals, bool retriesFirst,
+                OrderedTxs& retries, ApplyFlags flags,
+                    IHashRouter& router,
+                        std::string const& suffix = "");
 
     /** Algorithm for applying transactions.
 
@@ -174,8 +176,8 @@ private:
     };
 
     std::shared_ptr<OpenView>
-    create (std::shared_ptr<
-        Ledger const> const& ledger);
+    create (Rules const& rules,
+        std::shared_ptr<Ledger const> const& ledger);
 
     static
     Result
diff --git a/src/ripple/app/ledger/impl/LedgerConsensusImp.cpp b/src/ripple/app/ledger/impl/LedgerConsensusImp.cpp
index 656ba703a..a5636245d 100644
--- a/src/ripple/app/ledger/impl/LedgerConsensusImp.cpp
+++ b/src/ripple/app/ledger/impl/LedgerConsensusImp.cpp
@@ -1157,8 +1157,15 @@ void LedgerConsensusImp::accept (std::shared_ptr<SHAMap> set)
         ledgerMaster_.pushLedger (newLCL, newOL);
 
     #if RIPPLE_OPEN_LEDGER
-        getApp().openLedger().accept(newLCL,
-            localTx, anyDisputes, retries, tapNONE,
+        auto const lastVal =
+            getApp().getLedgerMaster().getValidatedLedger();
+        boost::optional<Rules> rules;
+        if (lastVal)
+            rules.emplace(*lastVal);
+        else
+            rules.emplace();
+        getApp().openLedger().accept(*rules,
+            newLCL, localTx, anyDisputes, retries, tapNONE,
                 getApp().getHashRouter(), "consensus");
         getApp().openLedger().verify(*newOL, "consensus after");
     #endif
diff --git a/src/ripple/app/ledger/impl/OpenLedger.cpp b/src/ripple/app/ledger/impl/OpenLedger.cpp
index 46b0c2ddb..7f467cca5 100644
--- a/src/ripple/app/ledger/impl/OpenLedger.cpp
+++ b/src/ripple/app/ledger/impl/OpenLedger.cpp
@@ -32,7 +32,7 @@ OpenLedger::OpenLedger(std::shared_ptr<
     : j_ (journal)
     , cache_ (cache)
     , config_ (config)
-    , current_ (create(ledger))
+    , current_ (create(ledger->rules(), ledger))
 {
 }
 
@@ -73,15 +73,15 @@ OpenLedger::modify (std::function<
 }
 
 void
-OpenLedger::accept(std::shared_ptr<
-    Ledger const> const& ledger,
+OpenLedger::accept(Rules const& rules,
+    std::shared_ptr<Ledger const> const& ledger,
         OrderedTxs const& locals, bool retriesFirst,
             OrderedTxs& retries, ApplyFlags flags,
                 IHashRouter& router, std::string const& suffix)
 {
     JLOG(j_.error) <<
         "accept ledger " << ledger->seq() << " " << suffix;
-    auto next = create(ledger);
+    auto next = create(rules, ledger);
     if (retriesFirst)
     {
         // Handle disputed tx, outside lock
@@ -121,11 +121,11 @@ OpenLedger::accept(std::shared_ptr<
 //------------------------------------------------------------------------------
 
 std::shared_ptr<OpenView>
-OpenLedger::create(std::shared_ptr<
-    Ledger const> const& ledger)
+OpenLedger::create (Rules const& rules,
+    std::shared_ptr<Ledger const> const& ledger)
 {
     return std::make_shared<OpenView>(
-        open_ledger, std::make_shared<
+        open_ledger, rules, std::make_shared<
             CachedLedger const>(ledger,
                 cache_));
 }
diff --git a/src/ripple/app/misc/NetworkOPs.cpp b/src/ripple/app/misc/NetworkOPs.cpp
index ef2750857..c385091b1 100644
--- a/src/ripple/app/misc/NetworkOPs.cpp
+++ b/src/ripple/app/misc/NetworkOPs.cpp
@@ -1322,7 +1322,14 @@ void NetworkOPsImp::switchLastClosedLedger (
 
     #if RIPPLE_OPEN_LEDGER
         auto retries = localTx;
-        getApp().openLedger().accept(
+        auto const lastVal =
+            getApp().getLedgerMaster().getValidatedLedger();
+        boost::optional<Rules> rules;
+        if (lastVal)
+            rules.emplace(*lastVal);
+        else
+            rules.emplace();
+        getApp().openLedger().accept(*rules,
             newLCL, OrderedTxs({}), false, retries,
                 tapNONE, getApp().getHashRouter(), "jump");
         getApp().openLedger().verify(
diff --git a/src/ripple/app/paths/RippleLineCache.cpp b/src/ripple/app/paths/RippleLineCache.cpp
index 816b7a309..11c773d0b 100644
--- a/src/ripple/app/paths/RippleLineCache.cpp
+++ b/src/ripple/app/paths/RippleLineCache.cpp
@@ -28,6 +28,7 @@ RippleLineCache::RippleLineCache(
 {
     // We want the caching that OpenView provides
     // And we need to own a shared_ptr to the input view
+    // VFALCO TODO This should be a CachedLedger
     mLedger = std::make_shared<OpenView>(&*ledger, ledger);
 }
 
diff --git a/src/ripple/ledger/ApplyViewImpl.h b/src/ripple/ledger/ApplyViewImpl.h
index 16aef0ac5..5786f9cba 100644
--- a/src/ripple/ledger/ApplyViewImpl.h
+++ b/src/ripple/ledger/ApplyViewImpl.h
@@ -53,8 +53,8 @@ public:
     ApplyViewImpl (ApplyViewImpl&&) = default;
 #endif
 
-    ApplyViewImpl (ReadView const* base,
-        ApplyFlags flags);
+    ApplyViewImpl(
+        ReadView const* base, ApplyFlags flags);
 
     /** Apply the transaction.
 
diff --git a/src/ripple/ledger/CachedView.h b/src/ripple/ledger/CachedView.h
index 8825e16f6..76e519450 100644
--- a/src/ripple/ledger/CachedView.h
+++ b/src/ripple/ledger/CachedView.h
@@ -77,6 +77,12 @@ public:
         return base_.fees();
     }
 
+    Rules const&
+    rules() const override
+    {
+        return base_.rules();
+    }
+
     boost::optional<key_type>
     succ (key_type const& key, boost::optional<
         key_type> last = boost::none) const override
diff --git a/src/ripple/ledger/OpenView.h b/src/ripple/ledger/OpenView.h
index c8e74bb97..e1a0b5cd1 100644
--- a/src/ripple/ledger/OpenView.h
+++ b/src/ripple/ledger/OpenView.h
@@ -54,6 +54,7 @@ private:
             Serializer const>, std::shared_ptr<
                 Serializer const>>>;
 
+    Rules rules_;
     txs_map txs_;
     LedgerInfo info_;
     ReadView const* base_;
@@ -69,6 +70,7 @@ public:
     OpenView (OpenView&& other)
         : ReadView (std::move(other))
         , TxsRawView (std::move(other))
+        , rules_ (std::move(other.rules_))
         , txs_ (std::move(other.txs_))
         , info_ (std::move(other.info_))
         , base_ (std::move(other.base_))
@@ -108,16 +110,20 @@ public:
             ownership of a copy of `hold` until
             the MetaView is destroyed.
 
+            Calls to rules() will return the
+            rules provided on construction.
+
         The tx list starts empty and will contain
         all newly inserted tx.
     */
     /** @{ */
-    OpenView (open_ledger_t, ReadView const* base,
-        std::shared_ptr<void const> hold = nullptr);
+    OpenView (open_ledger_t,
+        ReadView const* base, Rules const& rules,
+            std::shared_ptr<void const> hold = nullptr);
 
-    OpenView (open_ledger_t, std::shared_ptr<
-            ReadView const> const& base)
-        : OpenView (open_ledger, &*base, base)
+    OpenView (open_ledger_t, Rules const& rules,
+            std::shared_ptr<ReadView const> const& base)
+        : OpenView (open_ledger, &*base, rules, base)
     {
     }
     /** @} */
@@ -128,6 +134,8 @@ public:
 
             The LedgerInfo is copied from the base.
 
+            The rules are inherited from the base.
+
         The tx list starts empty and will contain
         all newly inserted tx.
     */
@@ -154,6 +162,9 @@ public:
     Fees const&
     fees() const override;
 
+    Rules const&
+    rules() const override;
+
     bool
     exists (Keylet const& k) const override;
 
diff --git a/src/ripple/ledger/PaymentSandbox.h b/src/ripple/ledger/PaymentSandbox.h
index 853cdf088..b1fc17a69 100644
--- a/src/ripple/ledger/PaymentSandbox.h
+++ b/src/ripple/ledger/PaymentSandbox.h
@@ -107,8 +107,7 @@ public:
     PaymentSandbox (PaymentSandbox&&) = default;
 #endif
 
-    PaymentSandbox (ReadView const* base,
-            ApplyFlags flags)
+    PaymentSandbox (ReadView const* base, ApplyFlags flags)
         : ApplyViewBase (base, flags)
     {
     }
@@ -134,14 +133,14 @@ public:
     /** @{ */
     explicit
     PaymentSandbox (PaymentSandbox const* base)
-        : ApplyViewBase (base, base->flags())
+        : ApplyViewBase(base, base->flags())
         , ps_ (base)
     {
     }
 
     explicit
     PaymentSandbox (PaymentSandbox* base)
-        : ApplyViewBase (base, base->flags())
+        : ApplyViewBase(base, base->flags())
         , ps_ (base)
     {
     }
diff --git a/src/ripple/ledger/ReadView.h b/src/ripple/ledger/ReadView.h
index d4135ee34..17124018a 100644
--- a/src/ripple/ledger/ReadView.h
+++ b/src/ripple/ledger/ReadView.h
@@ -104,17 +104,59 @@ struct LedgerInfo
     std::uint32_t closeTime = 0;
 };
 
-// ledger close flags
-static
-std::uint32_t const sLCF_NoConsensusTime = 1;
+//------------------------------------------------------------------------------
 
-inline
-bool getCloseAgree (LedgerInfo const& info)
+class DigestAwareReadView;
+
+/** Rules controlling protocol behavior. */
+class Rules
 {
-    return (info.closeFlags & sLCF_NoConsensusTime) == 0;
-}
+private:
+    class Impl;
 
-void addRaw (LedgerInfo const&, Serializer&);
+    std::shared_ptr<Impl const> impl_;
+
+public:
+    Rules (Rules const&) = default;
+    Rules& operator= (Rules const&) = default;
+
+    /** Construct an empty rule set.
+
+        These are the rules reflected by
+        the genesis ledger.
+    */
+    Rules() = default;
+
+    /** Construct rules from a ledger.
+
+        The ledger contents are analyzed for rules
+        and amendments and extracted to the object.
+    */
+    explicit
+    Rules (DigestAwareReadView const& ledger);
+
+    /** Returns `true` if a feature is enabled. */
+    bool
+    enabled (uint256 const& feature) const;
+
+    /** Returns `true` if these rules don't match the ledger. */
+    bool
+    changed (DigestAwareReadView const& ledger) const;
+
+    /** Returns `true` if two rule sets are identical.
+
+        @note This is for diagnostics. To determine if new
+        rules should be constructed, call changed() first instead.
+    */
+    bool
+    operator== (Rules const&) const;
+
+    bool
+    operator!= (Rules const& other) const
+    {
+        return ! (*this == other);
+    }
+};
 
 //------------------------------------------------------------------------------
 
@@ -214,6 +256,11 @@ public:
     Fees const&
     fees() const = 0;
 
+    /** Returns the tx processing rules. */
+    virtual
+    Rules const&
+    rules() const = 0;
+
     /** Determine if a state item exists.
 
         @note This can be more efficient than calling read.
@@ -344,6 +391,20 @@ public:
     digest (key_type const& key) const = 0;
 };
 
+//------------------------------------------------------------------------------
+
+// ledger close flags
+static
+std::uint32_t const sLCF_NoConsensusTime = 1;
+
+inline
+bool getCloseAgree (LedgerInfo const& info)
+{
+    return (info.closeFlags & sLCF_NoConsensusTime) == 0;
+}
+
+void addRaw (LedgerInfo const&, Serializer&);
+
 } // ripple
 
 #include <ripple/ledger/detail/ReadViewFwdRange.ipp>
diff --git a/src/ripple/ledger/Sandbox.h b/src/ripple/ledger/Sandbox.h
index 9de4d1c1a..371205972 100644
--- a/src/ripple/ledger/Sandbox.h
+++ b/src/ripple/ledger/Sandbox.h
@@ -49,14 +49,13 @@ public:
     Sandbox (Sandbox&&) = default;
 #endif
 
-    Sandbox (ReadView const* base,
-            ApplyFlags flags)
+    Sandbox (ReadView const* base, ApplyFlags flags)
         : ApplyViewBase (base, flags)
     {
     }
 
     Sandbox (ApplyView const* base)
-        : Sandbox (base, base->flags())
+        : Sandbox(base, base->flags())
     {
     }
 
diff --git a/src/ripple/ledger/detail/ApplyViewBase.h b/src/ripple/ledger/detail/ApplyViewBase.h
index 4165e8a4b..7d76c85ea 100644
--- a/src/ripple/ledger/detail/ApplyViewBase.h
+++ b/src/ripple/ledger/detail/ApplyViewBase.h
@@ -52,8 +52,8 @@ public:
     ApplyViewBase (ApplyViewBase&&) = default;
 #endif
 
-    ApplyViewBase (ReadView const* base,
-        ApplyFlags flags);
+    ApplyViewBase(
+        ReadView const* base, ApplyFlags flags);
 
     // ReadView
 
@@ -63,6 +63,9 @@ public:
     Fees const&
     fees() const override;
 
+    Rules const&
+    rules() const override;
+
     bool
     exists (Keylet const& k) const override;
 
diff --git a/src/ripple/ledger/impl/ApplyViewBase.cpp b/src/ripple/ledger/impl/ApplyViewBase.cpp
index 14853ec12..143bd1add 100644
--- a/src/ripple/ledger/impl/ApplyViewBase.cpp
+++ b/src/ripple/ledger/impl/ApplyViewBase.cpp
@@ -25,8 +25,7 @@ namespace ripple {
 namespace detail {
 
 ApplyViewBase::ApplyViewBase(
-    ReadView const* base,
-        ApplyFlags flags)
+    ReadView const* base, ApplyFlags flags)
     : flags_ (flags)
     , base_ (base)
 {
@@ -46,6 +45,12 @@ ApplyViewBase::fees() const
     return base_->fees();
 }
 
+Rules const&
+ApplyViewBase::rules() const
+{
+    return base_->rules();
+}
+
 bool
 ApplyViewBase::exists (Keylet const& k) const
 {
diff --git a/src/ripple/ledger/impl/ApplyViewImpl.cpp b/src/ripple/ledger/impl/ApplyViewImpl.cpp
index 8edb0c7c1..6d2634f98 100644
--- a/src/ripple/ledger/impl/ApplyViewImpl.cpp
+++ b/src/ripple/ledger/impl/ApplyViewImpl.cpp
@@ -20,12 +20,12 @@
 #include <BeastConfig.h>
 #include <ripple/ledger/ApplyViewImpl.h>
 #include <ripple/basics/contract.h>
+#include <cassert>
 
 namespace ripple {
 
 ApplyViewImpl::ApplyViewImpl(
-    ReadView const* base,
-        ApplyFlags flags)
+    ReadView const* base, ApplyFlags flags)
     : ApplyViewBase (base, flags)
 {
 }
diff --git a/src/ripple/ledger/impl/OpenView.cpp b/src/ripple/ledger/impl/OpenView.cpp
index 659f6de6c..cf40cabcd 100644
--- a/src/ripple/ledger/impl/OpenView.cpp
+++ b/src/ripple/ledger/impl/OpenView.cpp
@@ -89,9 +89,10 @@ public:
 //------------------------------------------------------------------------------
 
 OpenView::OpenView (open_ledger_t,
-    ReadView const* base,
+    ReadView const* base, Rules const& rules,
         std::shared_ptr<void const> hold)
-    : info_ (base->info())
+    : rules_ (rules)
+    , info_ (base->info())
     , base_ (base)
     , hold_ (std::move(hold))
 {
@@ -102,7 +103,8 @@ OpenView::OpenView (open_ledger_t,
 
 OpenView::OpenView (ReadView const* base,
         std::shared_ptr<void const> hold)
-    : info_ (base->info())
+    : rules_ (base->rules())
+    , info_ (base->info())
     , base_ (base)
     , hold_ (std::move(hold))
 {
@@ -138,6 +140,12 @@ OpenView::fees() const
     return base_->fees();
 }
 
+Rules const&
+OpenView::rules() const
+{
+    return rules_;
+}
+
 bool
 OpenView::exists (Keylet const& k) const
 {
diff --git a/src/ripple/ledger/impl/ReadView.cpp b/src/ripple/ledger/impl/ReadView.cpp
index 884ef4dac..ee941d5fb 100644
--- a/src/ripple/ledger/impl/ReadView.cpp
+++ b/src/ripple/ledger/impl/ReadView.cpp
@@ -19,9 +19,105 @@
 
 #include <BeastConfig.h>
 #include <ripple/ledger/ReadView.h>
+#include <boost/optional.hpp>
 
 namespace ripple {
 
+class Rules::Impl
+{
+private:
+    std::unordered_set<uint256,
+        hardened_hash<>> set_;
+    boost::optional<uint256> digest_;
+
+public:
+    Impl (DigestAwareReadView const& ledger)
+    {
+        auto const k = keylet::amendments();
+        digest_ = ledger.digest(k.key);
+        if (! digest_)
+            return;
+        auto const sle = ledger.read(k);
+        if (! sle)
+        {
+            // LogicError() ?
+            return;
+        }
+
+        for (auto const& item :
+                sle->getFieldV256(sfAmendments))
+            set_.insert(item);
+    }
+
+    bool
+    enabled (uint256 const& feature) const
+    {
+        return set_.count(feature) > 0;
+    }
+
+    bool
+    changed (DigestAwareReadView const& ledger) const
+    {
+        auto const digest =
+            ledger.digest(keylet::amendments().key);
+        if (! digest && ! digest_)
+            return false;
+        if (! digest || ! digest_)
+            return true;
+        return *digest != *digest_;
+    }
+
+    bool
+    operator== (Impl const& other) const
+    {
+        if (! digest_ && ! other.digest_)
+            return true;
+        if (! digest_ || ! other.digest_)
+            return false;
+        return *digest_ == *other.digest_;
+    }
+};
+
+//------------------------------------------------------------------------------
+
+Rules::Rules (DigestAwareReadView const& ledger)
+    : impl_(std::make_shared<Impl>(ledger))
+{
+}
+
+bool
+Rules::enabled (uint256 const& feature) const
+{
+    if (! impl_)
+        return false;
+    return impl_->enabled(feature);
+}
+
+bool
+Rules::changed (DigestAwareReadView const& ledger) const
+{
+    if (! impl_)
+        return static_cast<bool>(
+            ledger.digest(keylet::amendments().key));
+    return impl_->changed(ledger);
+}
+
+bool
+Rules::operator== (Rules const& other) const
+{
+#if 0
+    if (! impl_ && ! other.impl_)
+        return true;
+    if (! impl_ || ! other.impl_)
+        return false;
+    return *impl_ == *other.impl_;
+#else
+    return impl_.get() == other.impl_.get();
+#endif
+}
+
+//------------------------------------------------------------------------------
+
 ReadView::sles_type::sles_type(
         ReadView const& view)
     : ReadViewFwdRange(view)
diff --git a/src/ripple/test/jtx/impl/Env.cpp b/src/ripple/test/jtx/impl/Env.cpp
index 3df2a83a8..b63f079ff 100644
--- a/src/ripple/test/jtx/impl/Env.cpp
+++ b/src/ripple/test/jtx/impl/Env.cpp
@@ -117,7 +117,7 @@ Env::close(NetClock::time_point const& closeTime)
             closeTime.time_since_epoch ()).count (),
         ledgerPossibleTimeResolutions[0], false);
     OrderedTxs locals({});
-    openLedger.accept(next, locals,
+    openLedger.accept(next->rules(), next, locals,
         false, retries, applyFlags(), *router);
     closed_ = next;
     cachedSLEs_.expire();