diff --git a/src/passport.a b/src/passport.a
index 950a48c..da105d1 100755
--- a/src/passport.a
+++ b/src/passport.a
@@ -385,6 +385,7 @@ AnalyzeTrack
          !source "patchers/mak.a"               ; gIsBoot0 && T02 only
          !source "patchers/jsr8635.a"           ; gIsBoot0 only
          !source "patchers/sierra.a"            ; gIsBoot0 only
+         !source "patchers/probs5.a"
 _endDOS33Patchers
          ;
          ; Diversi-DOS-specific patchers
diff --git a/src/patchers/probs5.a b/src/patchers/probs5.a
new file mode 100644
index 0000000..9345a9e
--- /dev/null
+++ b/src/patchers/probs5.a
@@ -0,0 +1,35 @@
+;-------------------------------
+; #PROBS5
+; sector check of track $23
+; usually found in PROBS5 file
+;
+; tested on
+; - Addition and Subtraction of Fractions Analyzer
+; - Addition and Subtraction of Fractions Worksheet
+; - Decimals Analyzer
+; - Decimals Worksheet
+; - Multiplication and Division of Fractions Analyzer
+; - Multiplication and Division of Fractions Worksheet
+; - Whole Numbers Analyzer
+; - Whole Numbers Worksheet
+;-------------------------------
+!zone {
+         lda   #$0F
+         sta   .sector+1
+.sector  lda   #$FF       ; modified at runtime
+         ldx   #$00
+         ldy   #$08
+         jsr   compare
+         !byte $00,$20, $FF,$0F ; DOS 3.3 file header
+         !byte $A9,$23    ; LDA #$23
+         !byte $8D,$EC    ; STA $..EC
+         bcs   +          ; passport-test-suite/Addition and Subtraction of Fractions Analyzer.woz [C=0] matches
+         jsr   PrintByID
+         !byte s_probs5
+         ldx   #$04
+         jsr   modify1
+         !byte $60        ; RTS
++        dec   .sector+1
+         bpl   .sector
+.exit
+}
diff --git a/src/strings/en.a b/src/strings/en.a
index 721d4c4..c50cd9b 100755
--- a/src/strings/en.a
+++ b/src/strings/en.a
@@ -217,6 +217,7 @@ StringTableLow            ; must be kept in sync with constants in enid.a
          !byte <.enlightenment
          !byte <.sfc
          !byte <.neosoft
+         !byte <.probs5
 
 StringTableHigh           ; must be kept in sync with constants in enid.a
          !byte >.header
@@ -373,11 +374,12 @@ StringTableHigh           ; must be kept in sync with constants in enid.a
          !byte >.enlightenment
          !byte >.sfc
          !byte >.neosoft
+         !byte >.probs5
 
 .passport
          !text "Passport ",$00
 .header
-         !text "@",s_passport,"by 4am@",s_space7,"@",s_space7," 2023-01-27",$00
+         !text "@",s_passport,"by 4am@",s_space7,"@",s_space7," 2023-03-26",$00
 .bar9
          !text "_________",$00
 .bar18
@@ -772,3 +774,5 @@ StringTableHigh           ; must be kept in sync with constants in enid.a
          !text "@",s_found,"SFC @",s_protectioncheck,$8D,$00
 .neosoft
          !text "@",s_found,"Neosoft @",s_protectioncheck,$8D,$00
+.probs5
+         !text "@",s_found,"PROBS5 @",s_protectioncheck,$8D,$00
diff --git a/src/strings/enid.a b/src/strings/enid.a
index 6936db8..2c4752f 100644
--- a/src/strings/enid.a
+++ b/src/strings/enid.a
@@ -155,3 +155,4 @@ s_enlightenmentb0 = $96
 s_enlightenment = $97
 s_sfc        = $98
 s_neosoft    = $99
+s_probs5     = $9A