diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4240797c8b..0dfdf833a2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,17 +7,20 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [Unreleased]
 
 ### changed
+- **21_trade** changed export share calculation to be done at region level in the model
 - **default.cfg** input data upgraded from rev4.117 to rev4.118, default for bioenergy demand and GHG prices changed from R32M46 to R34M410, `rcp4p5` used for SSP2-NPi2025 in line with MAGICC climate outcome and REMIND assumptions.
+- **default.cfg** changed running magpie by default with optfile for specified solver settings (Tol_Optimality)
 - **script/start/test_runs.R** Test runs adjusted based on availability from coupled runs for R34M410. 
 
 ### added
--
+- **default.cfg** added option to set Tol_Optimality (GAMS solver setting) to a certain value (GAMS-default 1e-7, new MAgPIE-default 1e-8)
+- **80_optimization** added writing of conopt opt files with using scalars from input 
 
 ### removed
--
+- **80_optimization** removed older optfile, that should be tried if no optimal solution can be found
 
 ### fixed
--
+- **18_residues** fixed equation for cluster level production of crop residues in flexreg_apr16 realization
 
 
 ## [4.10.0] - 2025-04-03
diff --git a/config/default.cfg b/config/default.cfg
index f2be8a9e02..7776f0afb7 100644
--- a/config/default.cfg
+++ b/config/default.cfg
@@ -597,8 +597,6 @@ cfg$gms$processing <- "substitution_may21"        # def = substitution_may21
 cfg$gms$c20_scp_type <- "sugar"                         # def = sugar
 
 # ***---------------------    21_trade    --------------------------------------
-# * (free_apr16):       free trade without restrictions
-# * (off):              no trade at all
 # * (exo):              exogenously prescribed trade
 # * (selfsuff_reduced): self-sufficiency based trade with trade costs related to exports
 # * (selfsuff_reduced_bilateral22): same as `selfsuff_reduced` but with bilateral trade flows
@@ -2177,7 +2175,12 @@ cfg$gms$c80_nlp_solver <- "conopt4"              # def = conopt4
 
 # * 1: using optfile for specified solver settings
 # * 0: default settings (optfile will be ignored)
-cfg$gms$s80_optfile <- 0 # def = 0
+cfg$gms$s80_optfile <- 1 # def = 1
+
+# Solver setting Tol_Optimality (real): 
+# Optimality tolerance for reduced gradient when feasible.
+# Range: [3.e-13, 1], Solver default: 1.e-7
+cfg$gms$s80_toloptimal <- 1.0e-8 # def = 1.0e-8
 
 # * Optional second solve statement (0=off, 1=on)
 cfg$gms$s80_secondsolve <- 0 # def = 0
diff --git a/core/calculations.gms b/core/calculations.gms
index 9063d06f87..e8c37db7e2 100644
--- a/core/calculations.gms
+++ b/core/calculations.gms
@@ -21,7 +21,6 @@ $batinclude "./modules/include.gms" preloop
 * to be done here because a file declaration cannot be inside a loop
 file dummy; dummy.pw=2000; put dummy;
 
-
 ************************OPTIMIZATION PROCESS START******************************
 * This section contains only sourcecode that is directly connected to the
 * optimization process. That means that everything on the following lines
diff --git a/modules/18_residues/flexreg_apr16/declarations.gms b/modules/18_residues/flexreg_apr16/declarations.gms
index e000474151..b4ce1a141c 100644
--- a/modules/18_residues/flexreg_apr16/declarations.gms
+++ b/modules/18_residues/flexreg_apr16/declarations.gms
@@ -18,19 +18,15 @@ positive variables
 ;
 
 equations
-
  q18_prod_res_ag_reg(i,kcr,attributes)     Production constraint of aboveground residues (mio. tDM)
  q18_prod_res_bg_reg(i,kcr,dm_nr)          Production constraint of belowground residues (mio. tDM)
-
  q18_res_field_balance(i,kcr,attributes)   Calculation of the residues amount recycled to soils (mio. tDM)
  q18_res_field_burn(i,kcr,attributes)      Fixing of the residues amount burned in a region in respective attribute units DM GJ Nr P K WM C (mio. tX)
  q18_translate(i,kres,attributes)          Transformation of the multiple crop residues into supply balance crop redisues in respective attribute units DM GJ Nr P K WM C (mio. tX)
- q18_prod_res_cell(j,kres)                 Allows for distribution of residues to cellular level (mio. tDM)
-
+ q18_prod_res_reg(i,kres)                 Allows for distribution of residues to cellular level (mio. tDM)
  q18_res_recycling_nr(i)                   Nutrient recycling of reaactive nitrogen (mio. tNr)
  q18_res_recycling_pk(i,pk18)              Nutrient recycling of phosphorus and potash (mio. tX)
  q18_cost_prod_res(i,kres)                 Production costs of harvesting crop residues (mio. USD17MER)
-
 ;
 
 parameters
@@ -52,7 +48,7 @@ parameters
  oq18_res_field_balance(t,i,kcr,attributes,type) Calculation of the residues amount recycled to soils (mio. tDM)
  oq18_res_field_burn(t,i,kcr,attributes,type)    Fixing of the residues amount burned in a region in respective attribute units DM GJ Nr P K WM C (mio. tX)
  oq18_translate(t,i,kres,attributes,type)        Transformation of the multiple crop residues into supply balance crop redisues in respective attribute units DM GJ Nr P K WM C (mio. tX)
- oq18_prod_res_cell(t,j,kres,type)               Allows for distribution of residues to cellular level (mio. tDM)
+ oq18_prod_res_reg(t,i,kres,type)                Allows for distribution of residues to cellular level (mio. tDM)
  oq18_res_recycling_nr(t,i,type)                 Nutrient recycling of reaactive nitrogen (mio. tNr)
  oq18_res_recycling_pk(t,i,pk18,type)            Nutrient recycling of phosphorus and potash (mio. tX)
  oq18_cost_prod_res(t,i,kres,type)               Production costs of harvesting crop residues (mio. USD17MER)
diff --git a/modules/18_residues/flexreg_apr16/equations.gms b/modules/18_residues/flexreg_apr16/equations.gms
index e01b0d2072..7bf6de8aad 100644
--- a/modules/18_residues/flexreg_apr16/equations.gms
+++ b/modules/18_residues/flexreg_apr16/equations.gms
@@ -73,10 +73,12 @@
                   vm_prod_reg(i2,kres) * fm_attributes(attributes,kres);
 
 *' Amount produced at cellular level is flexible, can be distributed as it wants 
- q18_prod_res_cell(j2,kres)..
-                  sum(cell(i2,j2), vm_prod_reg(i2,kres))
+*' and is just bound by the regional sum via
+
+ q18_prod_res_reg(i2,kres)..
+                  sum(cell(i2,j2), v18_prod_res(j2,kres))
                   =e=
-                  v18_prod_res(j2,kres) ;
+                  vm_prod_reg(i2,kres);
 
 
 *' Residues recycled to croplands in nutrients `vm_res_recycling(i2,"nr")` are
diff --git a/modules/18_residues/flexreg_apr16/postsolve.gms b/modules/18_residues/flexreg_apr16/postsolve.gms
index 0b0007332b..4633ea69e2 100644
--- a/modules/18_residues/flexreg_apr16/postsolve.gms
+++ b/modules/18_residues/flexreg_apr16/postsolve.gms
@@ -23,7 +23,7 @@
  oq18_res_field_balance(t,i,kcr,attributes,"marginal") = q18_res_field_balance.m(i,kcr,attributes);
  oq18_res_field_burn(t,i,kcr,attributes,"marginal")    = q18_res_field_burn.m(i,kcr,attributes);
  oq18_translate(t,i,kres,attributes,"marginal")        = q18_translate.m(i,kres,attributes);
- oq18_prod_res_cell(t,j,kres,"marginal")               = q18_prod_res_cell.m(j,kres);
+ oq18_prod_res_reg(t,i,kres,"marginal")                = q18_prod_res_reg.m(i,kres);
  oq18_res_recycling_nr(t,i,"marginal")                 = q18_res_recycling_nr.m(i);
  oq18_res_recycling_pk(t,i,pk18,"marginal")            = q18_res_recycling_pk.m(i,pk18);
  oq18_cost_prod_res(t,i,kres,"marginal")               = q18_cost_prod_res.m(i,kres);
@@ -40,7 +40,7 @@
  oq18_res_field_balance(t,i,kcr,attributes,"level")    = q18_res_field_balance.l(i,kcr,attributes);
  oq18_res_field_burn(t,i,kcr,attributes,"level")       = q18_res_field_burn.l(i,kcr,attributes);
  oq18_translate(t,i,kres,attributes,"level")           = q18_translate.l(i,kres,attributes);
- oq18_prod_res_cell(t,j,kres,"level")                  = q18_prod_res_cell.l(j,kres);
+ oq18_prod_res_reg(t,i,kres,"level")                   = q18_prod_res_reg.l(i,kres);
  oq18_res_recycling_nr(t,i,"level")                    = q18_res_recycling_nr.l(i);
  oq18_res_recycling_pk(t,i,pk18,"level")               = q18_res_recycling_pk.l(i,pk18);
  oq18_cost_prod_res(t,i,kres,"level")                  = q18_cost_prod_res.l(i,kres);
@@ -57,7 +57,7 @@
  oq18_res_field_balance(t,i,kcr,attributes,"upper")    = q18_res_field_balance.up(i,kcr,attributes);
  oq18_res_field_burn(t,i,kcr,attributes,"upper")       = q18_res_field_burn.up(i,kcr,attributes);
  oq18_translate(t,i,kres,attributes,"upper")           = q18_translate.up(i,kres,attributes);
- oq18_prod_res_cell(t,j,kres,"upper")                  = q18_prod_res_cell.up(j,kres);
+ oq18_prod_res_reg(t,i,kres,"upper")                   = q18_prod_res_reg.up(i,kres);
  oq18_res_recycling_nr(t,i,"upper")                    = q18_res_recycling_nr.up(i);
  oq18_res_recycling_pk(t,i,pk18,"upper")               = q18_res_recycling_pk.up(i,pk18);
  oq18_cost_prod_res(t,i,kres,"upper")                  = q18_cost_prod_res.up(i,kres);
@@ -74,7 +74,7 @@
  oq18_res_field_balance(t,i,kcr,attributes,"lower")    = q18_res_field_balance.lo(i,kcr,attributes);
  oq18_res_field_burn(t,i,kcr,attributes,"lower")       = q18_res_field_burn.lo(i,kcr,attributes);
  oq18_translate(t,i,kres,attributes,"lower")           = q18_translate.lo(i,kres,attributes);
- oq18_prod_res_cell(t,j,kres,"lower")                  = q18_prod_res_cell.lo(j,kres);
+ oq18_prod_res_reg(t,i,kres,"lower")                   = q18_prod_res_reg.lo(i,kres);
  oq18_res_recycling_nr(t,i,"lower")                    = q18_res_recycling_nr.lo(i);
  oq18_res_recycling_pk(t,i,pk18,"lower")               = q18_res_recycling_pk.lo(i,pk18);
  oq18_cost_prod_res(t,i,kres,"lower")                  = q18_cost_prod_res.lo(i,kres);
diff --git a/modules/21_trade/exo/not_used.txt b/modules/21_trade/exo/not_used.txt
new file mode 100644
index 0000000000..4dd79412da
--- /dev/null
+++ b/modules/21_trade/exo/not_used.txt
@@ -0,0 +1,2 @@
+name,type,reason
+sm_fix_SSP2,input,not needed
diff --git a/modules/21_trade/free_apr16/declarations.gms b/modules/21_trade/free_apr16/declarations.gms
deleted file mode 100644
index 6654381530..0000000000
--- a/modules/21_trade/free_apr16/declarations.gms
+++ /dev/null
@@ -1,29 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-parameters
- i21_trade_bal_reduction(t_all,k_trade)         Trade balance reduction (1)
- i21_trade_margin(h,k_trade)                    Trade margins (USD17MER per tDM)
- i21_trade_tariff(h,k_trade)                    Trade tariffs (USD17MER per tDM)
-;
-
-positive variables
- vm_cost_trade(i)                            Regional  trade costs (mio. USD17MER per yr)
-;
-
-equations
- q21_trade_glo(k_trade)          Global production constraint (mio. tDM per yr)
- q21_notrade(h,k_notrade)        Superregional production constraint of non-tradable commodities (mio. tDM per yr)
-;
-
-*#################### R SECTION START (OUTPUT DECLARATIONS) ####################
-parameters
- ov_cost_trade(t,i,type)          Regional  trade costs (mio. USD17MER per yr)
- oq21_trade_glo(t,k_trade,type)   Global production constraint (mio. tDM per yr)
- oq21_notrade(t,h,k_notrade,type) Superregional production constraint of non-tradable commodities (mio. tDM per yr)
-;
-*##################### R SECTION END (OUTPUT DECLARATIONS) #####################
diff --git a/modules/21_trade/free_apr16/equations.gms b/modules/21_trade/free_apr16/equations.gms
deleted file mode 100644
index 3926ac0232..0000000000
--- a/modules/21_trade/free_apr16/equations.gms
+++ /dev/null
@@ -1,18 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-*' @equations
-*' For traded goods the only active constraint is that the global supply is larger or equal to demand.
-*' This means that production can be freely allocated globally based on comparative advantages.
-
-q21_trade_glo(k_trade).. sum(i2 ,vm_prod_reg(i2,k_trade)) =g= sum(i2, vm_supply(i2,k_trade));
-
-*'
-*' For non-tradable commodites, the regional supply should be larger or equal to the regional demand.
-
- q21_notrade(h2,k_notrade)..
-   sum(supreg(h2,i2),vm_prod_reg(i2,k_notrade)) =g= sum(supreg(h2,i2), vm_supply(i2,k_notrade));
diff --git a/modules/21_trade/free_apr16/input.gms b/modules/21_trade/free_apr16/input.gms
deleted file mode 100644
index 24f41963ec..0000000000
--- a/modules/21_trade/free_apr16/input.gms
+++ /dev/null
@@ -1,11 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-table f21_self_suff(t_all,h,kall) Superregional self-sufficiency rates (1)
-$ondelim
-$include "./modules/21_trade/input/f21_trade_self_suff.cs3"
-$offdelim;
diff --git a/modules/21_trade/free_apr16/postsolve.gms b/modules/21_trade/free_apr16/postsolve.gms
deleted file mode 100644
index b405f11f5b..0000000000
--- a/modules/21_trade/free_apr16/postsolve.gms
+++ /dev/null
@@ -1,22 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-
-*#################### R SECTION START (OUTPUT DEFINITIONS) #####################
- ov_cost_trade(t,i,"marginal")          = vm_cost_trade.m(i);
- oq21_trade_glo(t,k_trade,"marginal")   = q21_trade_glo.m(k_trade);
- oq21_notrade(t,h,k_notrade,"marginal") = q21_notrade.m(h,k_notrade);
- ov_cost_trade(t,i,"level")             = vm_cost_trade.l(i);
- oq21_trade_glo(t,k_trade,"level")      = q21_trade_glo.l(k_trade);
- oq21_notrade(t,h,k_notrade,"level")    = q21_notrade.l(h,k_notrade);
- ov_cost_trade(t,i,"upper")             = vm_cost_trade.up(i);
- oq21_trade_glo(t,k_trade,"upper")      = q21_trade_glo.up(k_trade);
- oq21_notrade(t,h,k_notrade,"upper")    = q21_notrade.up(h,k_notrade);
- ov_cost_trade(t,i,"lower")             = vm_cost_trade.lo(i);
- oq21_trade_glo(t,k_trade,"lower")      = q21_trade_glo.lo(k_trade);
- oq21_notrade(t,h,k_notrade,"lower")    = q21_notrade.lo(h,k_notrade);
-*##################### R SECTION END (OUTPUT DEFINITIONS) ######################
diff --git a/modules/21_trade/free_apr16/realization.gms b/modules/21_trade/free_apr16/realization.gms
deleted file mode 100644
index 5d69350249..0000000000
--- a/modules/21_trade/free_apr16/realization.gms
+++ /dev/null
@@ -1,19 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-*' @description  In this realization, agricultural trade is fully liberalized in all timesteps. 
-
-*' @limitations This realization does not account for current trends in agricultural trade.
-
-*####################### R SECTION START (PHASES) ##############################
-$Ifi "%phase%" == "sets" $include "./modules/21_trade/free_apr16/sets.gms"
-$Ifi "%phase%" == "declarations" $include "./modules/21_trade/free_apr16/declarations.gms"
-$Ifi "%phase%" == "input" $include "./modules/21_trade/free_apr16/input.gms"
-$Ifi "%phase%" == "equations" $include "./modules/21_trade/free_apr16/equations.gms"
-$Ifi "%phase%" == "preloop" $include "./modules/21_trade/free_apr16/preloop.gms"
-$Ifi "%phase%" == "postsolve" $include "./modules/21_trade/free_apr16/postsolve.gms"
-*######################## R SECTION END (PHASES) ###############################
diff --git a/modules/21_trade/free_apr16/sets.gms b/modules/21_trade/free_apr16/sets.gms
deleted file mode 100644
index 0a23e00b10..0000000000
--- a/modules/21_trade/free_apr16/sets.gms
+++ /dev/null
@@ -1,22 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-sets
-*sets should be in sync with default trade realisation; currently selfsuff_reduced 
-   k_notrade(kall) Production activities of non-tradable commodites
-       / oilpalm, foddr, pasture, res_cereals, res_fibrous, res_nonfibrous, begr,betr /
-* oilpalm not traded, only its oil and oilcake due to FAOSTAT complications, and as trade is little
-* foddr is not traded as too bulky
-* pasture it not traded as too bulky
-* begr and betr are not traded because biomass is traded in REMIND
-   k_trade(kall) Production activities of tradable commodities
-   / tece,maiz,trce,rice_pro,soybean,rapeseed,groundnut,sunflower,puls_pro,
-   potato,cassav_sp,sugr_cane,sugr_beet,others,cottn_pro,
-   oils,oilcakes,sugar,molasses,alcohol,ethanol,distillers_grain,brans,scp,fibres,
-   livst_rum, livst_pig,livst_chick, livst_egg, livst_milk, fish, wood, woodfuel /
-
-;
diff --git a/modules/21_trade/input/files b/modules/21_trade/input/files
index dbc4131c7f..5b70512a5d 100644
--- a/modules/21_trade/input/files
+++ b/modules/21_trade/input/files
@@ -1,6 +1,6 @@
 * list of files that are required here
 f21_trade_self_suff.cs3
-f21_trade_export_share.cs3
+f21_trade_domestic_supply.cs3
 f21_trade_balanceflow.cs3
 f21_trade_margin.cs3
 f21_trade_tariff.cs3
diff --git a/modules/21_trade/module.gms b/modules/21_trade/module.gms
index ea081a3124..0e62aed9df 100644
--- a/modules/21_trade/module.gms
+++ b/modules/21_trade/module.gms
@@ -16,8 +16,6 @@
 *' @authors  Xiaoxi Wang, Anne Biewald, Christoph Schmitz, Markus Bonsch
 *###################### R SECTION START (MODULETYPES) ##########################
 $Ifi "%trade%" == "exo" $include "./modules/21_trade/exo/realization.gms"
-$Ifi "%trade%" == "free_apr16" $include "./modules/21_trade/free_apr16/realization.gms"
-$Ifi "%trade%" == "off" $include "./modules/21_trade/off/realization.gms"
 $Ifi "%trade%" == "selfsuff_reduced" $include "./modules/21_trade/selfsuff_reduced/realization.gms"
 $Ifi "%trade%" == "selfsuff_reduced_bilateral22" $include "./modules/21_trade/selfsuff_reduced_bilateral22/realization.gms"
 *###################### R SECTION END (MODULETYPES) ############################
diff --git a/modules/21_trade/off/declarations.gms b/modules/21_trade/off/declarations.gms
deleted file mode 100644
index 834bc74db3..0000000000
--- a/modules/21_trade/off/declarations.gms
+++ /dev/null
@@ -1,21 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-positive variables
- vm_cost_trade(i)                            Regional  trade costs (mio. USD17MER per yr)
-;
-
-equations
- q21_notrade(h,kall)   Superregional production constraint of non-tradable commodities (mio. tDM per yr)
-;
-
-*#################### R SECTION START (OUTPUT DECLARATIONS) ####################
-parameters
- ov_cost_trade(t,i,type)     Regional  trade costs (mio. USD17MER per yr)
- oq21_notrade(t,h,kall,type) Superregional production constraint of non-tradable commodities (mio. tDM per yr)
-;
-*##################### R SECTION END (OUTPUT DECLARATIONS) #####################
diff --git a/modules/21_trade/off/equations.gms b/modules/21_trade/off/equations.gms
deleted file mode 100644
index a7f78a3132..0000000000
--- a/modules/21_trade/off/equations.gms
+++ /dev/null
@@ -1,13 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-*' @equations
-*' For all commodites, the regional supply should be larger or equal to the
-*' regional demand.
-
-q21_notrade(h2,kall)..
-  sum(supreg(h2,i2),vm_prod_reg(i2,kall)) =g= sum(supreg(h2,i2), vm_supply(i2,kall));
diff --git a/modules/21_trade/off/input.gms b/modules/21_trade/off/input.gms
deleted file mode 100644
index e13b626af9..0000000000
--- a/modules/21_trade/off/input.gms
+++ /dev/null
@@ -1,16 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-table f21_trade_balance(t_all,h,kall) trade balance of positive exports and negative imports (mio. tDM per yr)
-$ondelim
-$include "./modules/21_trade/input/f21_trade_balance.cs3"
-$offdelim;
-
-table f21_self_suff(t_all,h,kall) Superregional self-sufficiency rates (1)
-$ondelim
-$include "./modules/21_trade/input/f21_trade_self_suff.cs3"
-$offdelim;
diff --git a/modules/21_trade/off/postsolve.gms b/modules/21_trade/off/postsolve.gms
deleted file mode 100644
index 3dfc56b519..0000000000
--- a/modules/21_trade/off/postsolve.gms
+++ /dev/null
@@ -1,18 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-
-*#################### R SECTION START (OUTPUT DEFINITIONS) #####################
- ov_cost_trade(t,i,"marginal")     = vm_cost_trade.m(i);
- oq21_notrade(t,h,kall,"marginal") = q21_notrade.m(h,kall);
- ov_cost_trade(t,i,"level")        = vm_cost_trade.l(i);
- oq21_notrade(t,h,kall,"level")    = q21_notrade.l(h,kall);
- ov_cost_trade(t,i,"upper")        = vm_cost_trade.up(i);
- oq21_notrade(t,h,kall,"upper")    = q21_notrade.up(h,kall);
- ov_cost_trade(t,i,"lower")        = vm_cost_trade.lo(i);
- oq21_notrade(t,h,kall,"lower")    = q21_notrade.lo(h,kall);
-*##################### R SECTION END (OUTPUT DEFINITIONS) ######################
diff --git a/modules/21_trade/off/preloop.gms b/modules/21_trade/off/preloop.gms
deleted file mode 100644
index e5db56cc6e..0000000000
--- a/modules/21_trade/off/preloop.gms
+++ /dev/null
@@ -1,9 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-*set vm_cost_trade zero in order to avoid a free variable
-vm_cost_trade.fx(i)               = 0;
diff --git a/modules/21_trade/off/realization.gms b/modules/21_trade/off/realization.gms
deleted file mode 100644
index 4a5f9f3fa0..0000000000
--- a/modules/21_trade/off/realization.gms
+++ /dev/null
@@ -1,19 +0,0 @@
-*** |  (C) 2008-2025 Potsdam Institute for Climate Impact Research (PIK)
-*** |  authors, and contributors see CITATION.cff file. This file is part
-*** |  of MAgPIE and licensed under AGPL-3.0-or-later. Under Section 7 of
-*** |  AGPL-3.0, you are granted additional permissions described in the
-*** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
-*** |  Contact: magpie@pik-potsdam.de
-
-*' @description In this realization, there is no agricultural trade, i.e. regions
-*' are fully self-sufficient and dependent on domestic production.
-
-*' @limitations This realization does not account for current trends in agricultural trade.
-
-*####################### R SECTION START (PHASES) ##############################
-$Ifi "%phase%" == "declarations" $include "./modules/21_trade/off/declarations.gms"
-$Ifi "%phase%" == "input" $include "./modules/21_trade/off/input.gms"
-$Ifi "%phase%" == "equations" $include "./modules/21_trade/off/equations.gms"
-$Ifi "%phase%" == "preloop" $include "./modules/21_trade/off/preloop.gms"
-$Ifi "%phase%" == "postsolve" $include "./modules/21_trade/off/postsolve.gms"
-*######################## R SECTION END (PHASES) ###############################
diff --git a/modules/21_trade/selfsuff_reduced/declarations.gms b/modules/21_trade/selfsuff_reduced/declarations.gms
index 74732e2631..ccf11f6a03 100644
--- a/modules/21_trade/selfsuff_reduced/declarations.gms
+++ b/modules/21_trade/selfsuff_reduced/declarations.gms
@@ -7,8 +7,11 @@
 
 parameters
  i21_trade_bal_reduction(t_all,k_trade)         Trade balance reduction (1)
+ i21_exp_shr(t_all,h,k_trade)                   Trade export shr (1)
  i21_trade_margin(h,k_trade)                    Trade margins (USD17MER per tDM)
  i21_trade_tariff(h,k_trade)                    Trade tariffs (USD17MER per tDM)
+ i21_exports(t_all,h,k_trade)                   Total exports (tDM)
+ i21_exp_glo(t_all,k_trade)                     Total global exports (tDM)
 ;
 
 positive variables
diff --git a/modules/21_trade/selfsuff_reduced/equations.gms b/modules/21_trade/selfsuff_reduced/equations.gms
index a2a624e2a3..0c387ac850 100644
--- a/modules/21_trade/selfsuff_reduced/equations.gms
+++ b/modules/21_trade/selfsuff_reduced/equations.gms
@@ -55,7 +55,7 @@
 
  q21_excess_supply(h2,k_trade)..
  v21_excess_prod(h2,k_trade) =e=
- v21_excess_dem(k_trade)*sum(ct,f21_exp_shr(ct,h2,k_trade));
+ v21_excess_dem(k_trade)*sum(ct,i21_exp_shr(ct,h2,k_trade));
 
 * Trade costs are associated with exporting superregions. They are dependent on net exports, trade margin, and tariffs.
 
diff --git a/modules/21_trade/selfsuff_reduced/input.gms b/modules/21_trade/selfsuff_reduced/input.gms
index 7c7ef24511..6cfe28dffd 100644
--- a/modules/21_trade/selfsuff_reduced/input.gms
+++ b/modules/21_trade/selfsuff_reduced/input.gms
@@ -29,9 +29,9 @@ $ondelim
 $include "./modules/21_trade/input/f21_trade_self_suff.cs3"
 $offdelim;
 
-table f21_exp_shr(t_all,h,kall) Superregional and crop-specific export share (1)
+table f21_dom_supply(t_all,h,kall) Superregional domestic supply (mio. tDM per yr)
 $ondelim
-$include "./modules/21_trade/input/f21_trade_export_share.cs3"
+$include "./modules/21_trade/input/f21_trade_domestic_supply.cs3"
 $offdelim;
 
 table f21_trade_balanceflow(t_all,kall) Domestic balance flows (mio. tDM per yr)
diff --git a/modules/21_trade/selfsuff_reduced/preloop.gms b/modules/21_trade/selfsuff_reduced/preloop.gms
index a35770df1c..8a1bfb2f5c 100644
--- a/modules/21_trade/selfsuff_reduced/preloop.gms
+++ b/modules/21_trade/selfsuff_reduced/preloop.gms
@@ -5,8 +5,22 @@
 *** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
 *** |  Contact: magpie@pik-potsdam.de
 
-i21_trade_bal_reduction(t_all,k_trade)=f21_trade_bal_reduction(t_all,"easytrade","%c21_trade_liberalization%");
+
+*' Trade liberalization i.e. shift from self-sufficiency fixed pool to free pool begins
+*' with sm_fix_SSP2 to keep values matching historical data until then.
+loop(t_all,
+ if(m_year(t_all) <= sm_fix_SSP2,
+ i21_trade_bal_reduction(t_all,k_trade)=f21_trade_bal_reduction(t_all,"easytrade","l909090r808080");
+ i21_trade_bal_reduction(t_all,k_hardtrade21)=f21_trade_bal_reduction(t_all,"hardtrade","l909090r808080");
+ else
+ i21_trade_bal_reduction(t_all,k_trade)=f21_trade_bal_reduction(t_all,"easytrade","%c21_trade_liberalization%");
 i21_trade_bal_reduction(t_all,k_hardtrade21)=f21_trade_bal_reduction(t_all,"hardtrade","%c21_trade_liberalization%");
+ );
+);
+
+i21_exports(t_all,h,k_trade) =  ((f21_self_suff(t_all,h,k_trade) * f21_dom_supply(t_all,h,k_trade)) - f21_dom_supply(t_all,h,k_trade))$(f21_self_suff(t_all,h,k_trade) > 1);
+i21_exp_glo(t_all,k_trade) = sum(h, i21_exports(t_all,h,k_trade));
+i21_exp_shr(t_all,h,k_trade) = i21_exports(t_all,h,k_trade) / (i21_exp_glo(t_all,k_trade) +  0.001$(i21_exp_glo(t_all,k_trade) = 0));
 
 i21_trade_margin(h,k_trade) = f21_trade_margin(h,k_trade);
 
diff --git a/modules/21_trade/selfsuff_reduced/realization.gms b/modules/21_trade/selfsuff_reduced/realization.gms
index 809c0ffba7..d506a989c4 100644
--- a/modules/21_trade/selfsuff_reduced/realization.gms
+++ b/modules/21_trade/selfsuff_reduced/realization.gms
@@ -9,7 +9,8 @@
 *' together with regional demands, establish a baseline value for the production of traded products in the superregions. 
 *' Production is then allowed to fluctuate freely within a band around this baseline value, 
 *' only being enforced to maintain the condition of global production exceeding global demand.
-*' The width of the production band is determined by the `i21_trade_bal_reduction` (ptb) factor.
+*' The width of the production band is determined by the `i21_trade_bal_reduction` (ptb) factor, which differentiates 
+*' itself by SSP after the year prescribed by sm_fix_SSP2.
 *'
 *' Effectively, this factor splits the global demand into two pools: The `ptb` share of demand goes 
 *' into a pool for which the origin of products is fixed by the self-sufficiency ratios and export shares.
diff --git a/modules/21_trade/selfsuff_reduced_bilateral22/not_used.txt b/modules/21_trade/selfsuff_reduced_bilateral22/not_used.txt
new file mode 100644
index 0000000000..4dd79412da
--- /dev/null
+++ b/modules/21_trade/selfsuff_reduced_bilateral22/not_used.txt
@@ -0,0 +1,2 @@
+name,type,reason
+sm_fix_SSP2,input,not needed
diff --git a/modules/80_optimization/lp_nlp_apr17/input.gms b/modules/80_optimization/lp_nlp_apr17/input.gms
index 3945d0c594..1486c3a2a0 100644
--- a/modules/80_optimization/lp_nlp_apr17/input.gms
+++ b/modules/80_optimization/lp_nlp_apr17/input.gms
@@ -6,16 +6,8 @@
 *** |  Contact: magpie@pik-potsdam.de
 
 scalars
-    s80_maxiter   maximal solve iterations if modelstat is > 2 (1)      / 30 /
-    s80_optfile     switch to use specfied solver settings (1)          / 0 /
-    s80_add_cplex   add cplex optimization after conopt4 (1)            / 0 /
-    s80_add_conopt3 add conopt3 optimization after conopt4 (1)          / 0 /
-    s80_secondsolve     second solve statement (binary)                 / 0 / 
+    s80_maxiter         maximal solve iterations if modelstat is > 2 (1)    / 30 /
+    s80_optfile         switch to use specfied solver settings (1)          / 1 /
+    s80_secondsolve     second solve statement (binary)                     / 0 /
+    s80_toloptimal      value for CONOPT4 Tol_Optimality                        / 1e-08 /
 ;
-
-
-$setglobal c80_nlp_solver  conopt4
-*   options:   (conopt3):         conopt3
-*              (conopt4):         conopt4
-*              (conopt4+cplex):   conopt4 followed by cplex with landdiff optimization
-*              (conopt4+conopt3): conopt4 followed by conopt3
diff --git a/modules/80_optimization/lp_nlp_apr17/solve.gms b/modules/80_optimization/lp_nlp_apr17/solve.gms
index d9306a5dbd..a8a3db3dca 100644
--- a/modules/80_optimization/lp_nlp_apr17/solve.gms
+++ b/modules/80_optimization/lp_nlp_apr17/solve.gms
@@ -34,12 +34,12 @@ $elseif "%c80_nlp_solver%" == "conopt4+conopt3"
   s80_add_conopt3   = 1;
 $endif
 
-$onecho > conopt4.opt
-Lim_Variable = 1.e25
-$offecho
+put optfile;
+put 'Tol_Optimality = ', s80_toloptimal:12:11 /;
+putclose optfile;
 
 $onecho > conopt4.op2
-Flg_Prep = FALSE
+Lim_Variable = 1.e25
 $offecho
 
 repeat(
@@ -143,7 +143,7 @@ $batinclude "./modules/include.gms" nl_relax
 
 * if solve stopped with an error, try it again with CONOPT4 and OPTFILE
     if((magpie.modelstat = 13),
-      display "WARNING: Modelstat 13 | retry without Conopt4 pre-processing";
+      display "WARNING: Modelstat 13 | Retry solve with CONOPT4 increasing largest allowable value";
       option nlp = conopt4;
       magpie.optfile = 2
       solve magpie USING nlp MINIMIZING vm_cost_glo;
diff --git a/modules/80_optimization/nlp_apr17/input.gms b/modules/80_optimization/nlp_apr17/input.gms
index 051075eec3..1486c3a2a0 100644
--- a/modules/80_optimization/nlp_apr17/input.gms
+++ b/modules/80_optimization/nlp_apr17/input.gms
@@ -7,6 +7,7 @@
 
 scalars
     s80_maxiter         maximal solve iterations if modelstat is > 2 (1)    / 30 /
-    s80_optfile         switch to use specfied solver settings (1)          / 0 /
-    s80_secondsolve     second solve statement (binary)                     / 0 / 
+    s80_optfile         switch to use specfied solver settings (1)          / 1 /
+    s80_secondsolve     second solve statement (binary)                     / 0 /
+    s80_toloptimal      value for CONOPT4 Tol_Optimality                        / 1e-08 /
 ;
diff --git a/modules/21_trade/free_apr16/preloop.gms b/modules/80_optimization/nlp_apr17/preloop.gms
similarity index 80%
rename from modules/21_trade/free_apr16/preloop.gms
rename to modules/80_optimization/nlp_apr17/preloop.gms
index e5db56cc6e..115c631cc6 100644
--- a/modules/21_trade/free_apr16/preloop.gms
+++ b/modules/80_optimization/nlp_apr17/preloop.gms
@@ -5,5 +5,5 @@
 *** |  MAgPIE License Exception, version 1.0 (see LICENSE file).
 *** |  Contact: magpie@pik-potsdam.de
 
-*set vm_cost_trade zero in order to avoid a free variable
-vm_cost_trade.fx(i)               = 0;
+File optfile /conopt4.opt/;
+
diff --git a/modules/80_optimization/nlp_apr17/realization.gms b/modules/80_optimization/nlp_apr17/realization.gms
index f4c3750a8a..dd35745758 100644
--- a/modules/80_optimization/nlp_apr17/realization.gms
+++ b/modules/80_optimization/nlp_apr17/realization.gms
@@ -14,5 +14,6 @@
 *####################### R SECTION START (PHASES) ##############################
 $Ifi "%phase%" == "declarations" $include "./modules/80_optimization/nlp_apr17/declarations.gms"
 $Ifi "%phase%" == "input" $include "./modules/80_optimization/nlp_apr17/input.gms"
+$Ifi "%phase%" == "preloop" $include "./modules/80_optimization/nlp_apr17/preloop.gms"
 $Ifi "%phase%" == "solve" $include "./modules/80_optimization/nlp_apr17/solve.gms"
 *######################## R SECTION END (PHASES) ###############################
diff --git a/modules/80_optimization/nlp_apr17/solve.gms b/modules/80_optimization/nlp_apr17/solve.gms
index ffdb6bfc0e..d9facfe83a 100644
--- a/modules/80_optimization/nlp_apr17/solve.gms
+++ b/modules/80_optimization/nlp_apr17/solve.gms
@@ -18,16 +18,12 @@ magpie.scaleopt  = 1 ;
 magpie.solprint  = 0 ;
 magpie.holdfixed = 1 ;
 
-$onecho > conopt4.opt
-Lim_Variable = 1.e25
-$offecho
+put optfile;
+put 'Tol_Optimality = ', s80_toloptimal:12:11 /;
+putclose optfile;
 
 $onecho > conopt4.op2
-Flg_Prep = FALSE
-$offecho
-
-$onecho > conopt4.op3
-Flg_NoDefc = TRUE
+Lim_Variable = 1.e25
 $offecho
 
 if(execerror > 0, 
@@ -62,14 +58,10 @@ if (magpie.modelstat > 2,
       option nlp = conopt4;
       magpie.optfile = 1;
     elseif s80_resolve_option = 3,
-      display "Modelstat > 2 | Retry solve with CONOPT4 w/o preprocessing";
+      display "Modelstat > 2 | Retry solve with CONOPT4 increasing largest allowable value";
       option nlp = conopt4;
       magpie.optfile = 2;
     elseif s80_resolve_option = 4,
-      display "Modelstat > 2 | Retry solve with CONOPT4 w/o search for definitional constraints";
-      option nlp = conopt4;
-      magpie.optfile = 3;
-    elseif s80_resolve_option = 5,
       display "Modelstat > 2 | Retry solve with CONOPT3";
       option nlp = conopt3;
       magpie.optfile = 0;
@@ -94,7 +86,7 @@ if (magpie.modelstat > 2,
 *   Otherwise, the repeat loop will never end.
     magpie.modelStat$(magpie.modelStat=NA) = 13;
 
-    s80_resolve_option$(s80_resolve_option >= 5) = 0;
+    s80_resolve_option$(s80_resolve_option >= 4) = 0;
 
     until (magpie.modelstat <= 2 or s80_counter >= s80_maxiter)
   );
diff --git a/modules/80_optimization/nlp_par/input.gms b/modules/80_optimization/nlp_par/input.gms
index 39891d8b17..1486c3a2a0 100644
--- a/modules/80_optimization/nlp_par/input.gms
+++ b/modules/80_optimization/nlp_par/input.gms
@@ -6,7 +6,8 @@
 *** |  Contact: magpie@pik-potsdam.de
 
 scalars
-    s80_maxiter         maximal solve iterations if modelstat is > 2 (1)  / 30 /
-    s80_optfile         switch to use specfied solver settings (1)        / 0 /
-    s80_secondsolve     second solve statement (binary)                   / 0 / 
+    s80_maxiter         maximal solve iterations if modelstat is > 2 (1)    / 30 /
+    s80_optfile         switch to use specfied solver settings (1)          / 1 /
+    s80_secondsolve     second solve statement (binary)                     / 0 /
+    s80_toloptimal      value for CONOPT4 Tol_Optimality                        / 1e-08 /
 ;
diff --git a/modules/80_optimization/nlp_par/solve.gms b/modules/80_optimization/nlp_par/solve.gms
index 87be8fa8de..198a2c48eb 100644
--- a/modules/80_optimization/nlp_par/solve.gms
+++ b/modules/80_optimization/nlp_par/solve.gms
@@ -21,16 +21,12 @@ magpie.solprint  = 0 ;
 magpie.holdfixed = 1 ;
 magpie.savepoint = 0;
 
-$onecho > conopt4.opt
-Lim_Variable = 1.e25
-$offecho
+put optfile;
+put 'Tol_Optimality = ', s80_toloptimal:12:11 /;
+putclose optfile;
 
 $onecho > conopt4.op2
-Flg_Prep = FALSE
-$offecho
-
-$onecho > conopt4.op3
-Flg_NoDefc = TRUE
+Lim_Variable = 1.e25
 $offecho
 
 h2(h) = no;
@@ -111,14 +107,10 @@ repeat
           option nlp = conopt4;
           magpie.optfile = 1;         
         elseif p80_resolve_option(h) = 3, 
-          display "Modelstat > 2 | Retry solve with CONOPT4 w/o preprocessing";
+          display "Modelstat > 2 | Retry solve with CONOPT4 increasing largest allowable value";
           option nlp = conopt4;
           magpie.optfile = 2;         
         elseif p80_resolve_option(h) = 4, 
-          display "Modelstat > 2 | Retry solve with CONOPT4 w/o search for definitional constraints";
-          option nlp = conopt4;
-          magpie.optfile = 3;         
-        elseif p80_resolve_option(h) = 5, 
           display "Modelstat > 2 | Retry solve with CONOPT3";
           option nlp = conopt3;
           magpie.optfile = 0;         
@@ -131,7 +123,7 @@ repeat
         option nlp = conopt4;
         magpie.optfile = s80_optfile; 
         
-        p80_resolve_option(h)$(p80_resolve_option(h) >= 5) = 0;
+        p80_resolve_option(h)$(p80_resolve_option(h) >= 4) = 0;
        );
     h2(h) = no;
     i2(i) = no;