diff --git a/tzfile.h b/tzfile.h
index 93310d7..59782f1 100644
--- a/tzfile.h
+++ b/tzfile.h
@@ -49,7 +49,8 @@ static char	tzfilehid[] = "%W%";
 
 struct tzhead {
 	char	tzh_magic[4];		/* TZ_MAGIC */
-	char	tzh_reserved[16];	/* reserved for future use */
+	char	tzh_version[1];		/* '\0' or '2' as of 2005 */
+	char	tzh_reserved[15];	/* reserved--must be zero */
 	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
 	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
 	char	tzh_leapcnt[4];		/* coded number of leap seconds */
@@ -83,19 +84,23 @@ struct tzhead {
 **					assumed to be local time
 */
 
+/*
+** If tzh_version is '2' or greater, the above is followed by a second instance
+** of tzhead and a second instance of the data in which each coded transition
+** time uses 8 rather than 4 chars,
+** then a POSIX-TZ-environment-variable-style string for use in handling
+** instants after the last transition time stored in the file
+** (with nothing between the newlines if there is no POSIX representation for
+** such instants).
+*/
+
 /*
 ** In the current implementation, "tzset()" refuses to deal with files that
 ** exceed any of the limits below.
 */
 
 #ifndef TZ_MAX_TIMES
-/*
-** The TZ_MAX_TIMES value below is enough to handle a bit more than a
-** year's worth of solar time (corrected daily to the nearest second) or
-** 138 years of Pacific Presidential Election time
-** (where there are three time zone transitions every fourth year).
-*/
-#define TZ_MAX_TIMES	370
+#define TZ_MAX_TIMES	1200
 #endif /* !defined TZ_MAX_TIMES */
 
 #ifndef TZ_MAX_TYPES