diff --git a/src/sas/readstat_sas.c b/src/sas/readstat_sas.c
index 5dfd583..84ff085 100644
--- a/src/sas/readstat_sas.c
+++ b/src/sas/readstat_sas.c
@@ -26,6 +26,13 @@ unsigned char sas7bdat_magic_number[32] = {
     0x09, 0xc7, 0x31, 0x8c,   0x18, 0x1f, 0x10, 0x11
 };
 
+unsigned char sas7bdat_magic_number_alt[32] = {
+    0x00, 0x00, 0x00, 0x00,   0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,   0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,   0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00,   0x18, 0x1f, 0x10, 0x11
+};
+
 unsigned char sas7bcat_magic_number[32] = {
     0x00, 0x00, 0x00, 0x00,   0x00, 0x00, 0x00, 0x00,
     0x00, 0x00, 0x00, 0x00,   0xc2, 0xea, 0x81, 0x63,
@@ -171,6 +178,7 @@ readstat_error_t sas_read_header(readstat_io_t *io, sas_header_info_t *hinfo,
         goto cleanup;
     }
     if (memcmp(header_start.magic, sas7bdat_magic_number, sizeof(sas7bdat_magic_number)) != 0 &&
+            memcmp(header_start.magic, sas7bdat_magic_number_alt, sizeof(sas7bdat_magic_number_alt)) != 0 &&
             memcmp(header_start.magic, sas7bcat_magic_number, sizeof(sas7bcat_magic_number)) != 0) {
         retval = READSTAT_ERROR_PARSE;
         goto cleanup;
@@ -309,9 +317,9 @@ readstat_error_t sas_read_header(readstat_io_t *io, sas_header_info_t *hinfo,
         retval = READSTAT_ERROR_READ;
         goto cleanup;
     }
-    char major, revision_tag;
-    int minor, revision;
-    if (sscanf(header_end.release, "%c.%04d%c%1d", &major, &minor, &revision_tag, &revision) != 4) {
+    char major, revision_tag, revision;
+    int minor;
+    if (sscanf(header_end.release, "%c.%04d%c%c", &major, &minor, &revision_tag, &revision) != 4) {
         retval = READSTAT_ERROR_PARSE;
         goto cleanup;
     }
@@ -327,12 +335,21 @@ readstat_error_t sas_read_header(readstat_io_t *io, sas_header_info_t *hinfo,
         goto cleanup;
     }
     // revision_tag is usually M, but J has been observed in the wild (not created with SAS?)
-    if (revision_tag != 'M' && revision_tag != 'J') {
+    // files have also been observed with TK in place of the revision details.
+    if (revision_tag != 'M' && revision_tag != 'J' && revision_tag != 'T') {
         retval = READSTAT_ERROR_PARSE;
         goto cleanup;
     }
     hinfo->minor_version = minor;
-    hinfo->revision = revision;
+    if (revision >= '0' && revision <= '9') {
+        hinfo->revision = revision - '0';
+    } else if (revision_tag == 'T' && revision == 'K') {
+        // files have been observed with TK in place of the revision details.
+        hinfo->revision = 0;
+    } else {
+        retval = READSTAT_ERROR_PARSE;
+        goto cleanup;
+    }
 
     if ((major == '8' || major == '9') && minor == 0 && revision == 0) {
         /* A bit of a hack, but most SAS installations are running a minor update */
diff --git a/src/sas/readstat_sas.h b/src/sas/readstat_sas.h
index 6b80c2f..e9dc268 100644
--- a/src/sas/readstat_sas.h
+++ b/src/sas/readstat_sas.h
@@ -114,6 +114,7 @@ typedef struct sas_text_ref_s {
 #define SAS_DEFAULT_FILE_VERSION  9
 
 extern unsigned char sas7bdat_magic_number[32];
+extern unsigned char sas7bdat_magic_number_alt[32];
 extern unsigned char sas7bcat_magic_number[32];
 
 uint64_t sas_read8(const char *data, int bswap);