Decentralized storage network Filecoin's expected mainnet launch window has been moved back amid continuing software work and a delay in its testnet schedule.

Developed by Protocol Labs, Filecoin is built on top of the peer-to-peer data storage network InterPlanetary File System (IPFS) and lets users buy and sell unused storage on an open market.

The market operates on the network’s native token, Filecoin. Clients can hire miners to store or distribute data and miners can, in turn, earn rewards by fulfilling the storage requests of clients. Much like Bitcoin, Filecoin miners compete with each other to mine blocks and earn rewards. But in this case, their mining power is proportional to active storage, which incentivizes them to collect and rent out as much storage as possible.

Filecoin conducted one of the largest token sales in 2017 and raised more than $200 million from accredited and institutional investors.

Launch window pushed to June/July

On Dec. 11, 2019, Filecoin launched its Testnet Phase 1, which allowed prospective storage miners, storage clients, and developers to participate in the project's first test network.

According to its tentative roadmap released that month, the team planned to finish Testnet Phase 1 in late Jan. 2020 and start Phase 2 right away. The mainnet launch, as estimated then, would likely take place in March 2020.

However, Filecoin announced a postponed launch window in its Jan. 2020 update and a further six-week delay in its most recent blog post, which was published on Feb. 19. Its public roadmap chart now shows a tentative start date for Testnet Phase 2 on April 20 and an estimated mainnet launch window between June 15 and July 17.

The delays are meant to “allow enough time for final protocol convergence and feature freeze” before kicking off Testnet Phase 2, according to the most recent blog post.

"While we are working to launch Testnet Phase 2 and mainnet as soon as possible, we have the responsibility to ensure that Filecoin will be secure at launch," the blog post said. "Our teams need some additional time to complete protocol development, cross-implementation interop, internal protocol security audit, and refine our cryptoeconomic constructions."

Notably, Filecoin also attributed the delay in part to the coronavirus outbreak in China, saying that community members there do not feel safe returning to work due to the risks.

"Some of our Chinese community members have directly asked us to wait to launch Testnet Phase 2 for two or three weeks, until they can safely return to work," the team wrote. "We hope that this 6-week launch delay will afford enough time for the situation to improve in China, and for all of our global communities to participate in the network without compromising their safety."

"As always, these dates are best estimates, and could potentially shift," the team added.

Recent progress

Developers have made a number of changes to the network since they first started testing efforts in Dec.

Besides addressing bugs and the risk of network attacks through fork upgrades and optimizing chain sync speeds and stability, the team also added two more implementations – fuhon by Soramitsu and forest by ChainSafe.

Testnet Phase 2 will be "a minimum two-month period of formal testing, validation, and security audits" and launch with “multiple feature-complete and interoperable implementations,” the team explained.

Its two existing implementations, lotus and go-filecoin, are almost at the point of full interoperability and have been integrated into the executable spec library. There will be an interop network with the two implementations within the next few weeks. The team will then work to interoperate fuhon and forest on the network.

After the interop testing is completed, there will be a one-week code freeze. Testnet Phase 2 will take place after the code freeze ends. Additionally, the team will finish its internal security audit before moving on to the second phase of testing.

The testnet is currently seeing more than 3.6 pebibytes (PiB) of storage capacity, according to the blog post, although the team expects the capacity to be “several orders of magnitude larger” for the mainnet.