diff --git a/development/Win32/packaging/installer/ChangeLog.txt b/development/Win32/packaging/installer/ChangeLog.txt
index 5a23905e31..096b2dcb80 100644
--- a/development/Win32/packaging/installer/ChangeLog.txt
+++ b/development/Win32/packaging/installer/ChangeLog.txt
@@ -1,6 +1,10 @@
 Changelog for LyX-224-1:
 - installs LyX 2.2.4
 - new Russian translation of the installer messages
+- fix installation of Arabic spell checker
+- new thesaurus for Arabic
+- updated thesaurus for Ukrainian
+- updated spell checker dictionaries for Arabic, Breton and Ukrainian
 
 
 Changelog for LyX-223-2:
diff --git a/development/Win32/packaging/installer/DictionaryMirrors.txt b/development/Win32/packaging/installer/DictionaryMirrors.txt
index 434ea15c65..99a459087e 100644
--- a/development/Win32/packaging/installer/DictionaryMirrors.txt
+++ b/development/Win32/packaging/installer/DictionaryMirrors.txt
@@ -1,29 +1,22 @@
-dfn
+astuteinternet
+ayera
+cfhcable
+cytranet
+excellmedia
 freefr
-cznic
-garr
-optimate
-kaz
-kent
-heanet
-hivelocity
-ignum
-internode
 iweb
 jaist
-netcologne
-switch
+kent
+liquidtelecom
 nchc
-ncu
-skylink
-tcpdiag
-tenet
-ufpr
-waia
-colocrossing
-citylan
-aarnet
+netcologne
+netix
+netcologne
+newcontinuum
+phoenixnap
+razaoinfo
 superb-dca2
-superb-dca3
-softlayer-ams
-softlayer-dal
+superb-sea2
+ufpr
+versaweb
+vorboss
diff --git a/development/Win32/packaging/installer/HunspellDictionaryNames.txt b/development/Win32/packaging/installer/HunspellDictionaryNames.txt
index ff7b1039b8..817adc9472 100644
--- a/development/Win32/packaging/installer/HunspellDictionaryNames.txt
+++ b/development/Win32/packaging/installer/HunspellDictionaryNames.txt
@@ -1,7 +1,7 @@
 af_ZA.aff
 af_ZA.dic
-ar_DZ.aff
-ar_DZ.dic
+ar_SA.aff
+ar_SA.dic
 be_BY.aff
 be_BY.dic
 bg_BG.aff
diff --git a/development/Win32/packaging/installer/ThesaurusDictionaryNames.txt b/development/Win32/packaging/installer/ThesaurusDictionaryNames.txt
index 6d19dfa053..27e248f6e3 100644
--- a/development/Win32/packaging/installer/ThesaurusDictionaryNames.txt
+++ b/development/Win32/packaging/installer/ThesaurusDictionaryNames.txt
@@ -1,3 +1,5 @@
+th_ar_SA_v2.dat
+th_ar_SA_v2.idx
 th_bg_BG_v2.dat
 th_bg_BG_v2.idx
 th_ca_ES_v2.dat
diff --git a/development/Win32/packaging/installer/include/dictionaries.nsh b/development/Win32/packaging/installer/include/dictionaries.nsh
index 8119a06eae..415b19cad9 100644
--- a/development/Win32/packaging/installer/include/dictionaries.nsh
+++ b/development/Win32/packaging/installer/include/dictionaries.nsh
@@ -43,8 +43,8 @@ Function FindDictionaries
   
   # read out the possible thesaurus filenames from the file	
   FileOpen $R5 "$INSTDIR\Resources\ThesaurusDictionaryNames.txt" r
-  ${for} $5 1 27
-   # the file has 54 lines, but we only need to check for one of the 2 thesaurus files per language
+  ${for} $5 1 28
+   # the file has 56 lines, but we only need to check for one of the 2 thesaurus files per language
    # therefore check only for every second line
    FileRead $R5 $String # $String is now the dictionary name
    FileRead $R5 $String # $String is now the dictionary name
@@ -77,11 +77,11 @@ Function DownloadHunspellDictionaries
    # if first download repository is not available try the other ones listed in "DictionaryMirrors.txt"
    FileOpen $R4 "$INSTDIR\Resources\DictionaryMirrors.txt" r
    
-   ${For} $4 1 29 # there are 29 mirrors in the file
+   ${For} $4 1 22 # there are 22 mirrors in the file
     FileRead $R4 $Search # $Search is now the mirror
     StrCpy $Search $Search -2 # delete the linebreak characters at the end
     Push $R0
-    inetc::get /TIMEOUT=5000 "http://$Search.dl.sourceforge.net/project/lyxwininstaller/hunspell/$String" "$INSTDIR\Resources\dicts\$String" /END
+    inetc::get /TIMEOUT=5000 "https://$Search.dl.sourceforge.net/project/lyxwininstaller/hunspell/$String" "$INSTDIR\Resources\dicts\$String" /END
     Pop $R0
     ${if} $R0 == "OK"
      ${ExitFor}
@@ -112,7 +112,7 @@ Function DownloadThesaurusDictionaries
  
  # read out the locations from the file	
  FileOpen $R5 "$INSTDIR\Resources\ThesaurusDictionaryNames.txt" r
- ${For} $5 1 54 # the file has 52 lines
+ ${For} $5 1 56 # the file has 56 lines
  
   FileRead $R5 $String # $String is now the thesaurus name
   StrCpy $R3 $String 5 3 # $R3 is now the thesaurus language code
@@ -123,11 +123,11 @@ Function DownloadThesaurusDictionaries
    # if first download repository is not available try the other ones listed in "DictionaryMirrors.txt"
    FileOpen $R4 "$INSTDIR\Resources\DictionaryMirrors.txt" r
    
-   ${For} $4 1 29 # there are 29 mirrors in the file
+   ${For} $4 1 22 # there are 22 mirrors in the file
     FileRead $R4 $Search # $Search is now the mirror
     StrCpy $Search $Search -2 # delete the linebreak characters at the end
     Push $R0
-    inetc::get /TIMEOUT=5000 "http://$Search.dl.sourceforge.net/project/lyxwininstaller/thesaurus/$String" "$INSTDIR\Resources\thes\$String" /END
+    inetc::get /TIMEOUT=5000 "https://$Search.dl.sourceforge.net/project/lyxwininstaller/thesaurus/$String" "$INSTDIR\Resources\thes\$String" /END
     Pop $R0
     ${if} $R0 == "OK"
      ${ExitFor}
diff --git a/development/Win32/packaging/installer/include/init.nsh b/development/Win32/packaging/installer/include/init.nsh
index f6e258dbc0..85e1350ff0 100644
--- a/development/Win32/packaging/installer/include/init.nsh
+++ b/development/Win32/packaging/installer/include/init.nsh
@@ -73,8 +73,8 @@ Section /o "Afrikaans" SecDAfrikaans
 SectionEnd
 
 Section /o "العربية" SecDArabic
- StrCpy $DictCodes "ar_DZ,$DictCodes"
- AddSize 2500
+ StrCpy $DictCodes "ar_SA,$DictCodes"
+ AddSize 7304
 SectionEnd
 
 Section /o "հայերեն" SecDArmenian
@@ -99,7 +99,7 @@ SectionEnd
 
 Section /o "Brezhoneg" SecDBreton 
  StrCpy $DictCodes "br_FR,$DictCodes"
- AddSize 5510
+ AddSize 5556
 SectionEnd
 
 Section /o "български" SecDBulgarian
@@ -426,7 +426,7 @@ SectionEnd
 
 Section /o "Українська" SecDUkrainian
  StrCpy $DictCodes "uk_UA,$DictCodes"
- AddSize 5555
+ AddSize 6375
 SectionEnd
 
 Section /o "اردو" SecDUrdu
@@ -444,6 +444,11 @@ SectionGroupEnd
 
 SectionGroup "$(SecThesaurus)" SecThesaurus
 
+Section /o "العربية" SecTArabic
+ StrCpy $ThesCodes "ar_SA,$ThesCodes"
+ AddSize 799
+SectionEnd
+
 Section /o "български" SecTBulgarian
  StrCpy $ThesCodes "bg_BG,$ThesCodes"
  AddSize 3020
@@ -599,7 +604,8 @@ Function .onInit
   ${if} $R0 == "5.0" # 2000
   ${orif} $R0 == "5.1" # XP
   ${orif} $R0 == "5.2" # 2003
-    MessageBox MB_OK|MB_ICONSTOP "${APP_NAME} ${APP_VERSION} requires Windows Vista or newer." /SD IDOK
+  ${orif} $R0 == "6.0" # Vista
+    MessageBox MB_OK|MB_ICONSTOP "${APP_NAME} ${APP_VERSION} requires Windows 7 or newer." /SD IDOK
     Quit
   ${endif}
   
@@ -725,7 +731,7 @@ Function .onInit
    SectionSetFlags ${SecDAfrikaans} $0
    SectionSetSize ${SecDAfrikaans} 0
   ${endif}
-  StrCpy $Search "ar_DZ"
+  StrCpy $Search "ar_SA"
   Call StrPoint
   ${if} $Pointer != "-1"
    IntOp $0 ${SF_SELECTED} | ${SF_RO}
@@ -1227,8 +1233,15 @@ Function .onInit
   # select sections of already installed thesaurus dictionaries, make them read-only
   # and set the necessary size to 0 bytes
   StrCpy $String $FoundThes
-  StrCpy $Search "bg_BG"
+  StrCpy $Search "ar_SA"
   Call StrPoint # function from LyXUtils.nsh
+  ${if} $Pointer != "-1"
+   IntOp $0 ${SF_SELECTED} | ${SF_RO}
+   SectionSetFlags ${SecTArabic} $0
+   SectionSetSize ${SecTArabic} 0
+  ${endif}
+  StrCpy $Search "bg_BG"
+  Call StrPoint
   ${if} $Pointer != "-1"
    IntOp $0 ${SF_SELECTED} | ${SF_RO}
    SectionSetFlags ${SecTBulgarian} $0