diff --git a/changelog.txt b/changelog.txt
index 74f80b3..9ac787f 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -5,6 +5,10 @@ Date: ???
     - Fix load failure with zh-cn locale. Resolves https://github.com/pyanodon/pybugreports/issues/1347
     - Added py.spoilage_enabled() which checks for the feature flag and mod setting
     - Added META:hide() and META:unhide() to hide/unhide the prototype from any in-game browser and factoriopedia
+    - Updated TECHNOLOGY:remove_prereq() and TECHNOLOGY:replace_prereq() annotations
+    - TECHNOLOGY:remove_prereq() will always fail if self.prerequesites is empty or nil
+    - Added TECHNOLOGY:replace_prereq(old, new)
+    - Updated py.global_prerequisite_replacer to use TECHNOLOGY:replace_prereq()
 ---------------------------------------------------------------------------------------------------
 Version: 3.0.41
 Date: 2025-12-28
diff --git a/lib/data-stage.lua b/lib/data-stage.lua
index 6cdfc14..67f04e6 100644
--- a/lib/data-stage.lua
+++ b/lib/data-stage.lua
@@ -309,9 +309,9 @@ end
 
 ---replace an item/fluid in every recipes ingredients/results
 ---best used to merge items that are duplicated in mods that should be the same
----@param old string
----@param new string
----@param blackrecipe (string | table)?
+---@param old data.ItemID
+---@param new data.ItemID
+---@param blackrecipe (data.RecipeID | data.RecipeID[])?
 py.global_item_replacer = function(old, new, blackrecipe)
     if not data.raw.item[old] and not data.raw.fluid[old] then
         local errstring = "Could not find item or fluid " .. old
@@ -335,31 +335,26 @@ py.global_item_replacer = function(old, new, blackrecipe)
 end
 
 ---replaces every instance of the old prerequesite with the new one. if the new one is omitted, removes the old prerequesite instead
----@param old string
----@param new? string
+---@param old data.TechnologyID
+---@param new? data.TechnologyID
 py.global_prerequisite_replacer = function(old, new)
-  if not data.raw.technology[old] then
-      log("WARNING @ py.global_prerequisite_replacer(): Technology " .. old .. " does not exist")
-      return
-  end
-  if new and not data.raw.technology[new] then
-      log("WARNING @ py.global_prerequisite_replacer(): Technology " .. new .. " does not exist")
-      return
-  end
-  if new then
-    for _, tech in pairs(data.raw.technology) do
-      for i, prereq in pairs(tech.prerequisites or {}) do
-        if prereq == old then
-          tech.prerequisites[i] = new
-          break
-        end
-      end
+    if not data.raw.technology[old] then
+        log("WARNING @ py.global_prerequisite_replacer(): Technology " .. old .. " does not exist")
+        return
+    end
+    if new and not data.raw.technology[new] then
+        log("WARNING @ py.global_prerequisite_replacer(): Technology " .. new .. " does not exist")
+        return
     end
-  else -- no need to do fancy checks, just remove it
-    for tech in pairs(data.raw.technology) do
-      TECHNOLOGY(tech):remove_prereq(old)
+    if new then
+        for tech in pairs(data.raw.technology) do
+            TECHNOLOGY(tech):replace_prereq(old, new)
+        end
+    else -- no need to do fancy checks, just remove it
+        for tech in pairs(data.raw.technology) do
+            TECHNOLOGY(tech):remove_prereq(old)
+        end
     end
-  end
 end
 
 ---adds a small icon to the top right corner of a recipe
diff --git a/lib/metas/technology.lua b/lib/metas/technology.lua
index e6f26d0..a48ad89 100644
--- a/lib/metas/technology.lua
+++ b/lib/metas/technology.lua
@@ -1,9 +1,10 @@
 ---@class data.TechnologyPrototype
 ---@field public standardize fun(): data.TechnologyPrototype
----@field public add_prereq fun(self, prereq_technology_name: string): data.TechnologyPrototype
----@field public remove_prereq fun(self, prereq_technology_name: string): data.TechnologyPrototype
----@field public remove_pack fun(self, science_pack_name: string): data.TechnologyPrototype
----@field public add_pack fun(self, science_pack_name: string): data.TechnologyPrototype
+---@field public add_prereq fun(self, prereq_technology_name: data.TechnologyID): data.TechnologyPrototype
+---@field public remove_prereq fun(self, prereq_technology_name: data.TechnologyID): data.TechnologyPrototype
+---@field public replace_prereq fun(self, old: data.TechnologyID, new: data.TechnologyID): data.TechnologyPrototype
+---@field public remove_pack fun(self, science_pack_name: data.ItemID): data.TechnologyPrototype
+---@field public add_pack fun(self, science_pack_name: data.ItemID): data.TechnologyPrototype
 TECHNOLOGY = setmetatable(data.raw.technology, {
     ---@param technology data.TechnologyPrototype
     __call = function(self, technology)
@@ -33,7 +34,7 @@ metas.standardize = function(self)
 end
 
 ---@param self data.TechnologyPrototype
----@param prereq_technology_name string
+---@param prereq_technology_name data.TechnologyID
 ---@return data.TechnologyPrototype self
 ---@return boolean success
 metas.add_prereq = function(self, prereq_technology_name)
@@ -57,13 +58,11 @@ metas.add_prereq = function(self, prereq_technology_name)
 end
 
 ---@param self data.TechnologyPrototype
----@param prereq_technology_name string
+---@param prereq_technology_name data.TechnologyID
 ---@return data.TechnologyPrototype self
 ---@return boolean success
 metas.remove_prereq = function(self, prereq_technology_name)
-    if not self.prerequisites then
-        return self, true -- should it be true? false?
-    end
+    self.prerequisites = self.prerequisites or {}
 
     for i, prereq in pairs(self.prerequisites) do
       if prereq == prereq_technology_name then
@@ -75,8 +74,23 @@ metas.remove_prereq = function(self, prereq_technology_name)
     return self, false -- remove prereq fails
 end
 
+--- Replace old prerequesite with the new one. Fails if the old one was not found.
+---@param self data.TechnologyPrototype
+---@param old data.TechnologyID
+---@param new data.TechnologyID
+---@return data.TechnologyPrototype self
+---@return boolean success
+metas.replace_prereq = function(self, old, new)
+    local _, success = self.remove_prereq(old)
+    if success then
+        return self.add_prereq(new) -- conditional on success of add_prereq
+    else
+        return self, false -- DNE, do not add
+    end
+end
+
 ---@param self data.TechnologyPrototype
----@param science_pack_name string
+---@param science_pack_name data.ItemID
 ---@return data.TechnologyPrototype self
 ---@return boolean success
 metas.remove_pack = function(self, science_pack_name)
@@ -96,7 +110,7 @@ end
 
 -- possible to add the same pack twice, should probably check for that
 ---@param self data.TechnologyPrototype
----@param science_pack_name string
+---@param science_pack_name data.ItemID
 ---@return data.TechnologyPrototype self
 ---@return boolean success
 metas.add_pack = function(self, science_pack_name)
@@ -117,4 +131,12 @@ metas.add_pack = function(self, science_pack_name)
     return self, true -- add pack succeeds
 end
 
+---@param self data.TechnologyPrototype
+---@return data.TechnologyPrototype self
+---@return boolean success
+metas.apply_staged_name = function(self)
+    self.localised_name = {"?", self.localised_name or "technology-name." .. self.name, {"technology-name.py-staged-technology", {"technology-name." .. self.name}}}
+    return self, true
+end
+
 return metas