diff --git a/core/dive.h b/core/dive.h
index ca0325192..f81423f24 100644
--- a/core/dive.h
+++ b/core/dive.h
@@ -1016,7 +1016,7 @@ extern void set_userid(const char *user_id);
 extern void set_informational_units(const char *units);
 extern void set_git_prefs(const char *prefs);
 
-extern const char *get_dive_date_c_string(timestamp_t when);
+extern char *get_dive_date_c_string(timestamp_t when);
 extern void update_setpoint_events(struct dive *dive, struct divecomputer *dc);
 #ifdef __cplusplus
 }
diff --git a/core/libdivecomputer.c b/core/libdivecomputer.c
index be0bb01a5..a666ca667 100644
--- a/core/libdivecomputer.c
+++ b/core/libdivecomputer.c
@@ -618,9 +618,9 @@ static dc_status_t libdc_header_parser(dc_parser_t *parser, device_data_t *devda
 	}
 
 	// Parse the divetime.
-	const char *date_string = get_dive_date_c_string(dive->when);
+	char *date_string = get_dive_date_c_string(dive->when);
 	dev_info(devdata, translate("gettextFromC", "Dive %d: %s"), import_dive_number, date_string);
-	free((void *)date_string);
+	free(date_string);
 
 	unsigned int divetime = 0;
 	rc = dc_parser_get_field(parser, DC_FIELD_DIVETIME, 0, &divetime);
@@ -802,9 +802,9 @@ static int dive_cb(const unsigned char *data, unsigned int size,
 
 	/* If we already saw this dive, abort. */
 	if (!devdata->force_download && find_dive(&dive->dc)) {
-		const char *date_string = get_dive_date_c_string(dive->when);
+		char *date_string = get_dive_date_c_string(dive->when);
 		dev_info(devdata, translate("gettextFromC", "Already downloaded dive at %s"), date_string);
-		free((void *)date_string);
+		free(date_string);
 		goto error_exit;
 	}
 
diff --git a/core/plannernotes.c b/core/plannernotes.c
index c0647ebe6..e05f27738 100644
--- a/core/plannernotes.c
+++ b/core/plannernotes.c
@@ -137,15 +137,15 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		dive->notes = strdup(buffer);
 		goto finished;
 	} else if (diveplan->surface_interval >= 48 * 60 *60) {
-		const char *current_date = get_current_date();
+		char *current_date = get_current_date();
 		len += snprintf(buffer + len, sz_buffer - len, "<div><b>%s (%s) %s %s</b><br>",
 			translate("gettextFromC", "Subsurface"),
 			subsurface_canonical_version(),
 			translate("gettextFromC", "dive plan</b> created on"),
 			current_date);
-		free((void *)current_date);
+		free(current_date);
 	} else {
-		const char *current_date = get_current_date();
+		char *current_date = get_current_date();
 		len += snprintf_loc(buffer + len, sz_buffer - len, "<div><b>%s (%s) %s %d:%02d) %s %s<br>",
 			translate("gettextFromC", "Subsurface"),
 			subsurface_canonical_version(),
@@ -153,7 +153,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 			FRACTION(diveplan->surface_interval / 60, 60),
 			translate("gettextFromC", "created on"),
 			current_date);
-		free((void *)current_date);
+		free(current_date);
 	}
 
 	if (prefs.display_variations && decoMode() != RECREATIONAL)
diff --git a/core/qthelper.cpp b/core/qthelper.cpp
index 6c4fc099c..fb32fabe5 100644
--- a/core/qthelper.cpp
+++ b/core/qthelper.cpp
@@ -976,13 +976,13 @@ QString get_short_dive_date_string(timestamp_t when)
 	return loc.toString(ts.toUTC(), QString(prefs.date_format_short) + " " + prefs.time_format);
 }
 
-const char *get_dive_date_c_string(timestamp_t when)
+char *get_dive_date_c_string(timestamp_t when)
 {
 	QString text = get_dive_date_string(when);
 	return copy_qstring(text);
 }
 
-extern "C" const char *get_current_date()
+extern "C" char *get_current_date()
 {
 	QDateTime ts(QDateTime::currentDateTime());;
 	QString current_date;
diff --git a/core/qthelper.h b/core/qthelper.h
index 02fc629f8..4c0dcda66 100644
--- a/core/qthelper.h
+++ b/core/qthelper.h
@@ -79,7 +79,7 @@ char *picturedir_string();
 const char *subsurface_user_agent();
 enum deco_mode decoMode();
 int parse_seabear_header(const char *filename, char **params, int pnr);
-const char *get_current_date();
+char *get_current_date();
 double cache_value(int tissue, int timestep, enum inertgas gas);
 void cache_insert(int tissue, int timestep, enum inertgas gas, double value);
 void print_qt_versions();