diff --git a/Makefile b/Makefile
index bfb9638..dcc7722 100644
--- a/Makefile
+++ b/Makefile
@@ -32,20 +32,23 @@ BRMSAPTOOL-DEPS=brmsaptool.scm testing.import.scm listing.import.scm	\
 	dictionary.import.scm month.import.scm period.import.scm	\
 	ansi.import.scm member-file.import.scm				\
 	command-line.import.scm members-base.import.scm			\
-	utils.import.scm primes.import.scm member-record.import.scm
+	utils.import.scm primes.import.scm member-record.import.scm	\
+	configuration.import.scm
 
 BRMSAPTOOL-SOURCES=brmsaptool.scm testing.scm listing.scm		\
 	dictionary.scm month.scm period.scm ansi.scm member-file.scm	\
 	command-line.scm members-base.scm utils.scm primes.scm		\
-	member-record.scm
+	member-record.scm configuration.scm
 
 BRMSAPTOOL-OBJS=testing.o listing.o month.o period.o ansi.o	\
 		member-file.o dictionary.o command-line.o	\
-		members-base.o utils.o primes.o member-record.o
+		members-base.o utils.o primes.o member-record.o	\
+		configuration.o
 
 BRMSAPTOOL-SHARED=testing.so listing.so month.so period.so ansi.so	\
 		member-file.so dictionary.so command-line.so		\
-		members-base.so utils.so primes.so member-record.so
+		members-base.so utils.so primes.so member-record.so	\
+		configuration.so
 
 brmsaptool: $(BRMSAPTOOL-DEPS)
 	$(CSC) -o $@ $<
@@ -97,7 +100,7 @@ month.so: month.o
 month.o: month.import.scm
 month.import.scm: $(MONTH-SOURCES)
 
-PERIOD-SOURCES=period.scm testing.import.scm month.import.scm
+PERIOD-SOURCES=period.scm testing.import.scm month.import.scm configuration.import.scm
 
 period.so: period.o
 period.o: period.import.scm
@@ -111,7 +114,8 @@ ansi.import.scm: $(ANSI-SOURCES)
 
 MEMBER-FILE-SOURCES=member-file.scm dictionary.import.scm	\
 	ansi.import.scm month.import.scm period.import.scm	\
-	listing.import.scm testing.import.scm
+	listing.import.scm testing.import.scm			\
+	configuration.import.scm
 
 member-file.so: member-file.o
 member-file.o: member-file.import.scm
@@ -126,7 +130,7 @@ command-line.import.scm: $(COMMAND-LINE-SOURCES)
 MEMBERS-BASE-SOURCES=members-base.scm testing.import.scm		\
 	utils.import.scm dictionary.import.scm member-file.import.scm	\
 	primes.import.scm member-record.import.scm ansi.import.scm	\
-	period.import.scm month.import.scm
+	period.import.scm month.import.scm configuration.import.scm
 
 members-base.so: members-base.o
 members-base.o: members-base.import.scm
@@ -146,8 +150,15 @@ primes.import.scm: $(PRIMES-SOURCES)
 
 MEMBER-RECORD-SOURCES=member-record.scm dictionary.import.scm		\
 	period.import.scm testing.import.scm month.import.scm		\
-	member-file.import.scm listing.import.scm ansi.import.scm
+	member-file.import.scm listing.import.scm ansi.import.scm	\
+	configuration.import.scm
 
 member-record.so: member-record.o
 member-record.o: member-record.import.scm
 member-record.import.scm: $(MEMBER-RECORD-SOURCES)
+
+CONFIGURATION-SOURCES=configuration.scm
+
+configuration.so: configuration.o
+configuration.o: configuration.import.scm
+configuration.import.scm: $(CONFIGURATION-SOURCES)
diff --git a/configuration.scm b/configuration.scm
new file mode 100644
index 0000000..8e6218d
--- /dev/null
+++ b/configuration.scm
@@ -0,0 +1,45 @@
+;;
+;; configuraiton.scm
+;;
+;; Configuration parameters used by various modules.
+;;
+;; ISC License
+;;
+;; Copyright 2023 Brmlab, z.s.
+;; Dominik Pantůček <dominik.pantucek@trustica.cz>
+;;
+;; Permission to use, copy, modify, and/or distribute this software
+;; for any purpose with or without fee is hereby granted, provided
+;; that the above copyright notice and this permission notice appear
+;; in all copies.
+;; 
+;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+;; WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+;; WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+;; AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
+;; CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+;; OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+;; NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+;; CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+;;
+
+(declare (unit configuration))
+
+(module
+ configuration
+ (
+  *current-month*
+  )
+
+ (import scheme
+	 (chicken base)
+	 (chicken time)
+	 (chicken time posix))
+
+ (define *current-month*
+   (make-parameter
+    (let ((d (seconds->local-time (current-seconds))))
+      (list (+ 1900 (vector-ref d 5))
+	    (vector-ref d 4)))))
+
+ )
diff --git a/member-file.scm b/member-file.scm
index 19954f7..f860e23 100644
--- a/member-file.scm
+++ b/member-file.scm
@@ -171,17 +171,17 @@
  ;; under key k. Special handling for start/stop symbols means given
  ;; value is prepended to given start/stop key (student/suspend) as
  ;; parsed month for later processing of student/suspend periods.
- (define (process-member-line d k v)
+ (define (process-member-line d k v line-number)
    (let ((ss (split-start/stop-symbol k)))
      (if ss
 	 (let ((pk (car ss))
 	       (pd (cadr ss))
 	       (vl (string-split v " ")))
-	   (if (null? vl)
+	   (if (null? vl) ; Should not happen - k/v parser already catches this
 	       (error 'process-member-line "Missing date for start/stop symbol" k)
 	       (let ((ds (car vl)))
 		 (dict-set d pk
-			   (cons (cons pd (string->month ds))
+			   (cons (list pd (string->month ds) line-number)
 				 (dict-ref d pk '()))))))
 	 (case k
 	   ((card desfire credit) (dict-set d k (cons v (dict-ref d k '()))))
@@ -294,7 +294,7 @@
 	 (let ((p (split-member-line (car ls) file-name lines line-number)))
 	   (loop (cdr ls)
 		 (if p
-		     (apply process-member-line r p)
+		     (process-member-line r (car p) (cadr p) line-number)
 		     r)
 		 (+ line-number 1))))))
 
diff --git a/member-record.scm b/member-record.scm
index 9403943..2b76e0c 100644
--- a/member-record.scm
+++ b/member-record.scm
@@ -55,7 +55,8 @@
 	 month
 	 member-file
 	 listing
-	 ansi)
+	 ansi
+	 configuration)
 
  ;; Prints human-readable information
  (define (print-member-record-info mr)
diff --git a/members-base.scm b/members-base.scm
index b84e8d0..3633c21 100644
--- a/members-base.scm
+++ b/members-base.scm
@@ -57,7 +57,8 @@
 	 member-record
 	 ansi
 	 period
-	 month)
+	 month
+	 configuration)
 
  ;; Gets all files and symbolic links from given directory. The
  ;; symbolic links are represented by cons cells with car being the
diff --git a/period.scm b/period.scm
index 9fe5d48..7d5257b 100644
--- a/period.scm
+++ b/period.scm
@@ -28,7 +28,6 @@
 (module
  period
  (
-  *current-month*
   sort-period-markers
   period-markers->periods
   period->duration
@@ -49,13 +48,8 @@
 	 (chicken format)
 	 (chicken string)
 	 month
-	 testing)
-
- (define *current-month*
-   (make-parameter
-    (let ((d (seconds->local-time (current-seconds))))
-      (list (+ 1900 (vector-ref d 5))
-	    (vector-ref d 4)))))
+	 testing
+	 configuration)
 
  ;; Sorts period markers (be it start or end) chronologically and
  ;; returns the sorted list.