diff --git a/content/docs/rfcs/13/README.md b/content/docs/rfcs/13/README.md
index 29185514..e85c6139 100644
--- a/content/docs/rfcs/13/README.md
+++ b/content/docs/rfcs/13/README.md
@@ -22,8 +22,13 @@ The high uptime requirement makes sure that no message is missed out hence a com
 Nevertheless, in case that storage provider nodes cannot afford high availability, the querying nodes may retrieve the historical messages from multiple sources to achieve a full and intact view of the past.
 
 The concept of "ephemeral" messages exists while using `13/WAKU2-STORE` as well.
-Any `WakuMessage` that has the `ephemeral` flag set to `true` MAY be ignored by the store service node, thereby reducing the amount of one-time use messages stored.
-Nodes SHOULD NOT not store messages with the `ephemeral` flag set to `true`.
+
+Any `WakuMessage` that has the `ttl` field set to `0` MAY be ignored by the store service node, thereby reducing the amount of one-time use messages stored.
+Nodes SHOULD NOT not store messages with the `ttl` field set to `0`.
+
+Nodes SHOULD store messages which satisfy the following constraints -
+1. `ttl > currentTime + Thr`, where `Thr` describes the network latency as well as clock asynchrony.
+2. `ttl` is unset, for backwards compatibility.
 
 # Security Consideration
 
diff --git a/content/docs/rfcs/14/README.md b/content/docs/rfcs/14/README.md
index 6b0bd7e8..8cb87e30 100644
--- a/content/docs/rfcs/14/README.md
+++ b/content/docs/rfcs/14/README.md
@@ -38,9 +38,9 @@ The `timestamp` field MAY be filled out to signify the time at which the message
 This field holds the Unix epoch time in nanoseconds. 
 Omitting it means the timestamp is unspecified.
 
-The `ephemeral` field MAY be set to signify the transient nature of the message.
-If the message SHOULD be stored by the [store protocol](/spec/13), then this field MUST be set to `false`, which is equivalent to omitting the field.
-If the message SHOULD NOT be stored by the [store protocol](/spec/13), then this field MUST be set to `true`.
+The `ttl` field MAY be filled out to signify the time at which the message must be considered invalid.
+This field holds the Unix epoch time in nanoseconds.
+Omitting it means the timestamp is unspecified, and by extension, the message SHOULD be stored without a time-to-live.
 
 See [13/WAKU2-STORE](/spec/13) for more details.