diff --git a/tools/updatepofiles.lpi b/tools/updatepofiles.lpi
index 8ec9698f59..efd3b79883 100644
--- a/tools/updatepofiles.lpi
+++ b/tools/updatepofiles.lpi
@@ -1,46 +1,44 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <CONFIG>
   <ProjectOptions>
-    <Version Value="9"/>
+    <Version Value="12"/>
     <PathDelim Value="\"/>
     <General>
       <Flags>
         <SaveOnlyProjectUnits Value="True"/>
         <MainUnitHasCreateFormStatements Value="False"/>
         <MainUnitHasTitleStatement Value="False"/>
+        <MainUnitHasScaledStatement Value="False"/>
       </Flags>
       <SessionStorage Value="InIDEConfig"/>
-      <MainUnit Value="0"/>
     </General>
-    <VersionInfo>
-      <StringTable ProductVersion=""/>
-    </VersionInfo>
-    <BuildModes Count="1">
-      <Item1 Name="default" Default="True"/>
+    <BuildModes>
+      <Item Name="default" Default="True"/>
     </BuildModes>
     <PublishOptions>
       <Version Value="2"/>
-      <IgnoreBinaries Value="False"/>
-      <IncludeFileFilter Value="*.(pas|pp|inc|lfm|lpr|lrs|lpi|lpk|sh|xml)"/>
-      <ExcludeFileFilter Value="*.(bak|ppu|ppw|o|so);*~;backup"/>
     </PublishOptions>
     <RunParams>
-      <local>
-        <FormatVersion Value="1"/>
-        <LaunchingApplication PathPlusParams="\usr\X11R6\bin\xterm -T 'Lazarus Run Output' -e $(LazarusDir)\tools\runwait.sh $(TargetCmdLine)"/>
-      </local>
+      <FormatVersion Value="2"/>
+      <Modes>
+        <Mode Name="default">
+          <local>
+            <LaunchingApplication PathPlusParams="\usr\X11R6\bin\xterm -T &apos;Lazarus Run Output&apos; -e $(LazarusDir)\tools\runwait.sh $(TargetCmdLine)"/>
+          </local>
+        </Mode>
+      </Modes>
     </RunParams>
-    <RequiredPackages Count="1">
-      <Item1>
+    <RequiredPackages>
+      <Item>
         <PackageName Value="LCL"/>
-      </Item1>
+      </Item>
     </RequiredPackages>
-    <Units Count="1">
-      <Unit0>
+    <Units>
+      <Unit>
         <Filename Value="updatepofiles.pas"/>
         <IsPartOfProject Value="True"/>
         <UnitName Value="UpdatePoFiles"/>
-      </Unit0>
+      </Unit>
     </Units>
   </ProjectOptions>
   <CompilerOptions>
@@ -49,5 +47,10 @@
     <SearchPaths>
       <IncludeFiles Value="$(ProjOutDir)"/>
     </SearchPaths>
+    <Linking>
+      <Debugging>
+        <DebugInfoType Value="dsDwarf3"/>
+      </Debugging>
+    </Linking>
   </CompilerOptions>
 </CONFIG>
diff --git a/tools/updatepofiles.pas b/tools/updatepofiles.pas
index 18bba4259f..045e635c6e 100644
--- a/tools/updatepofiles.pas
+++ b/tools/updatepofiles.pas
@@ -1,4 +1,3 @@
-{  $Id$  }
 {
  ***************************************************************************
  *                                                                         *
@@ -25,20 +24,42 @@
        updatepofiles - updates po files.
 
   Synopsis:
-       updatepofiles filename1.pot [filename2.pot ... filenameN.pot]
+       updatepofiles [--searchdir=<dir>] [filenameA.rsj [filenameB.rsj ... filenameN.rsj]] filename1.pot [filename2.pot ... filenameN.pot]
 
   Description:
-       updatepofiles updates the .pot file and merges new strings into
-       all translated po files (filename1.*.po)
+       Updatepofiles updates the .pot file from .rsj (or .rst/.lrj) files and merges new strings into
+       all translated po files (filename1.*.po).
 
+       Examples:
+
+       1. Only update .po files:
+          updatepofiles /path/to/project1.pot
+
+       2. Update .pot file from .rsj and then .po files:
+          updatepofiles /path/to/fileA.rsj /path/to/project1.pot
+
+       3. Update .pot file from several .rsj files:
+          updatepofiles /path/to/fileA.rsj /path/to/fileB.rsj /path/to/project1.pot
+
+       4. Same as 2, but search .rsj in specified directory and its subdirectories:
+          updatepofiles --searchdir=<dir> fileA.rsj /path/to/project1.pot
+
+       Arguments can be repeated as needed, e. g.:
+
+       updatepofiles /path/to/fileA.rsj /path/to/project1.pot /path/to/fileB.rsj /path/to/project2.pot
+
+       will update project1.pot from fileA.rsj and project2.pot from fileB.rsj respectively.
 }
 program UpdatePoFiles;
 
 {$mode objfpc}{$H+}
 
 uses
-  Classes, SysUtils, Translations, LazFileUtils, LazUTF8;
-  
+  Classes, SysUtils, Translations, LazFileUtils, LazUTF8, FileUtil;
+
+const
+  ResSearchDirParamName='--searchdir=';
+
 var
   Files: TStringList;
   Prefix: string;
@@ -64,49 +85,100 @@ begin
       ResFiles[i].Free;
 end;
 
+function TryFindResFile(ResSearchDir, FileName: string): string;
+var
+  FileNameOnly: String;
+  FL: TStringList;
+  i: integer;
+begin
+  Result:='';
+  if ResSearchDir<>'' then
+  begin
+    FileNameOnly:=ExtractFileName(FileName); //make sure that path to file is removed
+    try
+      FL:=FindAllFiles(ResSearchDir, FileNameOnly, True);
+      if FL.Count>0 then
+      begin
+        Result:=FL[0];
+        i:=1;
+        while i<FL.Count do
+        begin
+          if FileAge(FL[i])>FileAge(Result) then
+            Result:=FL[i];
+          inc(i);
+        end;
+      end;
+    finally
+      FL.Free;
+    end;
+  end;
+  //writeln('Found resource string table file: ', Result);
+end;
+
 function ParamsValid: boolean;
 var
   i: Integer;
+  ResSearchDir: String;
+  CurParam: String;
   Filename: String;
   Ext: String;
   PoIndex: Integer;
+  IsResFile: Boolean;
 begin
   Result:=false;
   PoIndex:=0;
+  ResSearchDir:='';
 
   if ParamCount<1 then
     exit;
 
-  for i:=1 to ParamCount do begin
+  for i:=1 to ParamCount do
+  begin
+    CurParam:=ParamStrUTF8(i);
+    if UTF8StartsText(ResSearchDirParamName, CurParam) then
+    begin
+      ResSearchDir:=RightStr(CurParam, Length(CurParam)-Length(ResSearchDirParamName));
+      writeln('Current resource string table file search directory: ', ResSearchDir);
+    end
+    else
+    begin
+      Filename:=CurParam;
 
-    Filename:=ParamStrUTF8(i);
+      Ext:=ExtractFileExt(Filename);
 
-    Ext:=ExtractFileExt(Filename);
+      if (Ext<>'.pot') and (Ext<>'.rst') and (Ext<>'.lrj') and (Ext<>'.rsj') then
+      begin
+        writeln('ERROR: invalid extension: ', Filename);
+        exit;
+      end;
 
-    if not FileExistsUTF8(Filename) then begin
+      IsResFile:=(Ext='.rst') or (Ext='.lrj') or (Ext='.rsj');
 
-      if (Ext='.rst') or (Ext='.lrj') or (Ext='.rsj') then
-        continue; // ignore resource files
+      if not FileExistsUTF8(Filename) then
+      begin
+        if IsResFile then
+          Filename:=TryFindResFile(ResSearchDir, Filename); // if resource file does not exist, search it in specified directory
 
-      writeln('ERROR: file not found: ',FileName);
-      exit;
+        if (Filename='') or (not IsResFile) then
+        begin
+          writeln('ERROR: file not found: ', FileName);
+          exit;
+        end;
+      end;
+
+      if Ext='.pot' then
+      begin
+        if Files=nil then
+          Files:=TStringList.Create;
+        Files.Add(Filename);
+        inc(PoIndex);
+        SetLength(ResFiles, Files.Count); // make sure Files and ResFiles are in sync
+      end
+      else
+        AddResFile(PoIndex, FileName);
     end;
-
-    if (Ext<>'.pot') and  (Ext<>'.rst') and (Ext<>'.lrj')  and (Ext<>'.rsj') then begin
-      writeln('ERROR: invalid extension: ',Filename);
-      exit;
-    end;
-
-    if Ext='.pot' then begin
-      if Files=nil then
-        Files:=TStringList.Create;
-      Files.Add(Filename);
-      inc(PoIndex);
-      SetLength(ResFiles, Files.Count); // make sure Files and ResFiles are in sync
-    end else
-      AddResFile(PoIndex, FileName);
   end;
-  Result:=true;
+  Result:=PoIndex>0; // at least one .pot file should be found
 end;
 
 procedure UpdateAllPoFiles;
@@ -123,7 +195,7 @@ begin
 
   if not ParamsValid then
     writeln('Usage: ',ExtractFileName(ParamStrUTF8(0))
-       ,' filename1.pot [filename2.pot ... filenameN.pot]')
+       ,' [--searchdir=<dir>] [filenameA.rsj [filenameB.rsj ... filenameN.rsj]] filename1.pot [filename2.pot ... filenameN.pot]')
   else
     UpdateAllPoFiles;