diff --git a/libraries/chain/db_update.cpp b/libraries/chain/db_update.cpp
index cccc3bb2..debb05a0 100644
--- a/libraries/chain/db_update.cpp
+++ b/libraries/chain/db_update.cpp
@@ -109,9 +109,7 @@ void database::clear_expired_transactions()
    //Transactions must have expired by at least two forking windows in order to be removed.
    auto& transaction_idx = static_cast<transaction_index&>(get_mutable_index(implementation_ids, impl_transaction_object_type));
    const auto& dedupe_index = transaction_idx.indices().get<by_expiration>();
-   const auto& global_parameters = get_global_properties().parameters;
-   while( !dedupe_index.empty()
-          && head_block_time() - dedupe_index.rbegin()->trx.expiration >= fc::seconds(global_parameters.maximum_expiration) )
+   while( (!dedupe_index.empty()) && (head_block_time() > dedupe_index.rbegin()->trx.expiration) )
       transaction_idx.remove(*dedupe_index.rbegin());
 }
 
diff --git a/libraries/chain/get_config.cpp b/libraries/chain/get_config.cpp
index 9f10ce78..1d81ecfb 100644
--- a/libraries/chain/get_config.cpp
+++ b/libraries/chain/get_config.cpp
@@ -45,7 +45,6 @@ fc::variant_object get_config()
    result[ "GRAPHENE_DEFAULT_MAX_TIME_UNTIL_EXPIRATION" ] = GRAPHENE_DEFAULT_MAX_TIME_UNTIL_EXPIRATION;
    result[ "GRAPHENE_DEFAULT_MAINTENANCE_INTERVAL" ] = GRAPHENE_DEFAULT_MAINTENANCE_INTERVAL;
    result[ "GRAPHENE_DEFAULT_MAINTENANCE_SKIP_SLOTS" ] = GRAPHENE_DEFAULT_MAINTENANCE_SKIP_SLOTS;
-   result[ "GRAPHENE_DEFAULT_MAX_EXPIRATION_SEC" ] = GRAPHENE_DEFAULT_MAX_EXPIRATION_SEC;
    result[ "GRAPHENE_MIN_UNDO_HISTORY" ] = GRAPHENE_MIN_UNDO_HISTORY;
    result[ "GRAPHENE_MAX_UNDO_HISTORY" ] = GRAPHENE_MAX_UNDO_HISTORY;
    result[ "GRAPHENE_MIN_BLOCK_SIZE_LIMIT" ] = GRAPHENE_MIN_BLOCK_SIZE_LIMIT;
diff --git a/libraries/chain/include/graphene/chain/config.hpp b/libraries/chain/include/graphene/chain/config.hpp
index 7256fbb2..3ad559ea 100644
--- a/libraries/chain/include/graphene/chain/config.hpp
+++ b/libraries/chain/include/graphene/chain/config.hpp
@@ -45,7 +45,6 @@
 #define GRAPHENE_DEFAULT_MAX_TIME_UNTIL_EXPIRATION (60*60*24) // seconds,  aka: 1 day
 #define GRAPHENE_DEFAULT_MAINTENANCE_INTERVAL  (60*60*24) // seconds, aka: 1 day
 #define GRAPHENE_DEFAULT_MAINTENANCE_SKIP_SLOTS 3  // number of slots to skip for maintenance interval
-#define GRAPHENE_DEFAULT_MAX_EXPIRATION_SEC (60*60) // 1 hour 
 
 #define GRAPHENE_MIN_UNDO_HISTORY 10
 #define GRAPHENE_MAX_UNDO_HISTORY 1000
diff --git a/libraries/chain/include/graphene/chain/protocol/chain_parameters.hpp b/libraries/chain/include/graphene/chain/protocol/chain_parameters.hpp
index ac91d777..1f0e8d76 100644
--- a/libraries/chain/include/graphene/chain/protocol/chain_parameters.hpp
+++ b/libraries/chain/include/graphene/chain/protocol/chain_parameters.hpp
@@ -41,7 +41,7 @@ namespace graphene { namespace chain {
       uint32_t                committee_proposal_review_period    = GRAPHENE_DEFAULT_COMMITTEE_PROPOSAL_REVIEW_PERIOD_SEC; ///< minimum time in seconds that a proposed transaction requiring committee authority may not be signed, prior to expiration
       uint32_t                maximum_transaction_size            = GRAPHENE_DEFAULT_MAX_TRANSACTION_SIZE; ///< maximum allowable size in bytes for a transaction
       uint32_t                maximum_block_size                  = GRAPHENE_DEFAULT_MAX_BLOCK_SIZE; ///< maximum allowable size in bytes for a block
-      uint32_t                maximum_expiration                  = GRAPHENE_DEFAULT_MAX_EXPIRATION_SEC; ///< maximum number of seconds in the future a transaction may expire
+      uint32_t                maximum_expiration                  = 0; ///< ignored, but included to ensure we don't hardfork; see #308
       uint32_t                maximum_time_until_expiration       = GRAPHENE_DEFAULT_MAX_TIME_UNTIL_EXPIRATION; ///< maximum lifetime in seconds for transactions to be valid, before expiring
       uint32_t                maximum_proposal_lifetime           = GRAPHENE_DEFAULT_MAX_PROPOSAL_LIFETIME_SEC; ///< maximum lifetime in seconds for proposed transactions to be kept, before expiring
       uint8_t                 maximum_asset_whitelist_authorities = GRAPHENE_DEFAULT_MAX_ASSET_WHITELIST_AUTHORITIES; ///< maximum number of accounts which an asset may list as authorities for its whitelist OR blacklist