--- a/net/netfilter/nfnetlink_acct.c
+++ b/net/netfilter/nfnetlink_acct.c
@@ -32,6 +32,7 @@
 struct nf_acct {
 	atomic64_t		pkts;
 	atomic64_t		bytes;
+	atomic_t		fmt;
 	struct list_head	head;
 	atomic_t		refcnt;
 	char			name[NFACCT_NAME_MAX];
@@ -63,9 +64,14 @@
 
 	if (matching) {
 		if (nlh->nlmsg_flags & NLM_F_REPLACE) {
-			/* reset counters if you request a replacement. */
+			/* reset counters if you request a replacement... */
 			atomic64_set(&matching->pkts, 0);
 			atomic64_set(&matching->bytes, 0);
+			/* ... and change the format */
+			if (tb[NFACCT_FMT]) {
+				atomic_set(&matching->fmt,
+				   be32_to_cpu(nla_get_be32(tb[NFACCT_FMT])));
+			}
 			return 0;
 		}
 		return -EBUSY;
@@ -85,6 +91,10 @@
 		atomic64_set(&nfacct->pkts,
 			     be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
 	}
+	if (tb[NFACCT_FMT]) {
+		atomic_set(&nfacct->fmt,
+			   be32_to_cpu(nla_get_be32(tb[NFACCT_FMT])));
+	}
 	atomic_set(&nfacct->refcnt, 1);
 	list_add_tail_rcu(&nfacct->head, &nfnl_acct_list);
 	return 0;
@@ -121,6 +131,7 @@
 	}
 	if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts)) ||
 	    nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes)) ||
+	    nla_put_be32(skb, NFACCT_FMT, htonl(atomic_read(&acct->fmt))) ||
 	    nla_put_be32(skb, NFACCT_USE, htonl(atomic_read(&acct->refcnt))))
 		goto nla_put_failure;
 
@@ -265,6 +276,7 @@
 	[NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
 	[NFACCT_BYTES] = { .type = NLA_U64 },
 	[NFACCT_PKTS] = { .type = NLA_U64 },
+	[NFACCT_FMT] = { .type = NLA_U32 },
 };
 
 static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
--- a/include/uapi/linux/netfilter/nfnetlink_acct.h
+++ b/include/uapi/linux/netfilter/nfnetlink_acct.h
@@ -18,6 +18,7 @@
 	NFACCT_NAME,
 	NFACCT_PKTS,
 	NFACCT_BYTES,
+	NFACCT_FMT,
 	NFACCT_USE,
 	__NFACCT_MAX
 };