diff --git a/src/fios.h b/src/fios.h
index 999632d313..bbe0b08b03 100644
--- a/src/fios.h
+++ b/src/fios.h
@@ -51,6 +51,8 @@ struct LoadCheckData {
 	std::string debug_log_data;
 	std::string debug_config_data;
 
+	bool sl_is_ext_version = false;
+
 	LoadCheckData() : error_data(nullptr), grfconfig(nullptr),
 			grf_compatibility(GLC_NOT_FOUND), gamelog_action(nullptr), gamelog_actions(0)
 	{
diff --git a/src/fios_gui.cpp b/src/fios_gui.cpp
index 5f66345797..0fa640130f 100644
--- a/src/fios_gui.cpp
+++ b/src/fios_gui.cpp
@@ -27,6 +27,7 @@
 #include "core/geometry_func.hpp"
 #include "gamelog.h"
 #include "stringfilter_type.h"
+#include "gamelog.h"
 
 #include "widgets/fios_widget.h"
 
@@ -68,6 +69,8 @@ void LoadCheckData::Clear()
 
 	this->debug_log_data.clear();
 	this->debug_config_data.clear();
+
+	this->sl_is_ext_version = false;
 }
 
 /** Load game/scenario with optional content download */
@@ -814,7 +817,21 @@ public:
 					/* Show a caption box asking whether the user is sure to overwrite the save */
 					ShowQuery(STR_SAVELOAD_OVERWRITE_TITLE_DIFFERENT_ID, STR_SAVELOAD_OVERWRITE_WARNING_DIFFERENT_ID, this, SaveLoadWindow::SaveGameConfirmationCallback);
 				} else if (_settings_client.gui.savegame_overwrite_confirm >= (known_id ? 3 : 2) && file_exists) {
-					ShowQuery(STR_SAVELOAD_OVERWRITE_TITLE, STR_SAVELOAD_OVERWRITE_WARNING, this, SaveLoadWindow::SaveGameConfirmationCallback);
+					if (!_load_check_data.sl_is_ext_version) {
+						const char *version = GamelogGetLastRevision(_load_check_data.gamelog_action, _load_check_data.gamelog_actions);
+
+						SetDParam(0, STR_SAVELOAD_OVERWRITE_TITLE);
+						std::string caption = GetString(STR_SAVELOAD_OVERWRITE_TITLE_DIFFERENT_VERSION_SUFFIX);
+
+						SetDParam(0, STR_SAVELOAD_OVERWRITE_WARNING);
+						SetDParam(1, (version != nullptr) ? STR_SAVELOAD_OVERWRITE_WARNING_VERSION_NAME : STR_EMPTY);
+						SetDParamStr(2, version);
+						std::string message = GetString(STR_SAVELOAD_OVERWRITE_WARNING_DIFFERENT_VERSION_SUFFIX);
+
+						ShowQuery(std::move(caption), std::move(message), this, SaveLoadWindow::SaveGameConfirmationCallback);
+					} else {
+						ShowQuery(STR_SAVELOAD_OVERWRITE_TITLE, STR_SAVELOAD_OVERWRITE_WARNING, this, SaveLoadWindow::SaveGameConfirmationCallback);
+					}
 				} else {
 					_switch_mode = SM_SAVE_GAME;
 				}
diff --git a/src/gamelog.cpp b/src/gamelog.cpp
index c0d2f95857..99aa178c20 100644
--- a/src/gamelog.cpp
+++ b/src/gamelog.cpp
@@ -809,3 +809,22 @@ void GamelogInfo(LoggedAction *gamelog_action, uint gamelog_actions, uint32 *las
 		}
 	}
 }
+
+const char *GamelogGetLastRevision(const LoggedAction *gamelog_action, uint gamelog_actions)
+{
+	for (uint i = gamelog_actions; i > 0; i--) {
+		const LoggedAction &la = gamelog_action[i - 1];
+		const LoggedChange *lcend = &(la.change[la.changes]);
+		for (const LoggedChange *lc = la.change; lc != lcend; lc++) {
+			switch (lc->ct) {
+				case GLCT_REVISION:
+					return lc->revision.text;
+					break;
+
+				default:
+					break;
+			}
+		}
+	}
+	return nullptr;
+}
diff --git a/src/gamelog.h b/src/gamelog.h
index 43cd84f3a2..f9ab0a47e0 100644
--- a/src/gamelog.h
+++ b/src/gamelog.h
@@ -62,5 +62,6 @@ void GamelogTestMode();
 bool GamelogGRFBugReverse(uint32 grfid, uint16 internal_id);
 
 void GamelogInfo(struct LoggedAction *gamelog_action, uint gamelog_actions, uint32 *last_ottd_rev, byte *ever_modified, bool *removed_newgrfs);
+const char *GamelogGetLastRevision(const struct LoggedAction *gamelog_action, uint gamelog_actions);
 
 #endif /* GAMELOG_H */
diff --git a/src/lang/extra/english.txt b/src/lang/extra/english.txt
index 69cbec1e9c..24035ba5ae 100644
--- a/src/lang/extra/english.txt
+++ b/src/lang/extra/english.txt
@@ -1198,7 +1198,10 @@ STR_LAI_BRIDGE_DESCRIPTION_RAILROAD_SIGNAL                      :Railway bridge
 STR_SAVELOAD_UNKNOWN_ID                                         :{YELLOW}This file may be from a different game.
 STR_SAVELOAD_DIFFERENT_ID                                       :{YELLOW}This file is from a different game.
 STR_SAVELOAD_OVERWRITE_TITLE_DIFFERENT_ID                       :{WHITE}Overwrite File (Different Game)
+STR_SAVELOAD_OVERWRITE_TITLE_DIFFERENT_VERSION_SUFFIX           :{STRING} (Different Version)
 STR_SAVELOAD_OVERWRITE_WARNING_DIFFERENT_ID                     :{YELLOW}Are you sure you want to overwrite the existing file?{}{}The file is from a different game.
+STR_SAVELOAD_OVERWRITE_WARNING_DIFFERENT_VERSION_SUFFIX         :{STRING}{}{}The file is from a different version{STRING1}.{}If overwritten the file will no longer be readable by the original version.
+STR_SAVELOAD_OVERWRITE_WARNING_VERSION_NAME                     : ({RAW_STRING})
 
 STR_MAPGEN_SNOW_LINE_HEIGHT                                     :{BLACK}Snow line height:
 STR_MAPGEN_SNOW_LINE_UP                                         :{BLACK}Move the snow line height one up
diff --git a/src/saveload/saveload.cpp b/src/saveload/saveload.cpp
index 5b38b11a4d..5ec0df9168 100644
--- a/src/saveload/saveload.cpp
+++ b/src/saveload/saveload.cpp
@@ -3587,6 +3587,7 @@ static SaveOrLoadResult DoLoad(LoadFilter *reader, bool load_check)
 	if (load_check) {
 		/* The only part from AfterLoadGame() we need */
 		if (_load_check_data.want_grf_compatibility) _load_check_data.grf_compatibility = IsGoodGRFConfigList(_load_check_data.grfconfig);
+		_load_check_data.sl_is_ext_version = _sl_is_ext_version;
 	} else {
 		GamelogStartAction(GLAT_LOAD);