In the current Walrus Devnet, the epoch is fixed. Anything stored on Walrus now will remain accessible until the Devnet is either redeployed or replaced with a Walrus Testnet. According to the current implementation, the data will not become inaccessible automatically after one epoch ends unless the network undergoes redevelopment or is deliberately replaced.

The current document and settings in the Walrus Devnet imply that data is available for the duration of the set epoch. In the case of an upgrade or a switch to a testnet, the data would indeed need to be re-uploaded to remain accessible. However, in the future versions of Walrus, there is an option to pay for multiple epochs to extend the accessibility of your data. In summary, within the existing Walrus Devnet framework, your data will remain available till the next major network redeployment or upgrade. Make sure to keep track of any network updates that might require data migration to ensure continuity.