Indexing: Add note on Firehose, remove version req on IPFS (#137)

Author: azf20

pages/en/indexing.mdx

@@ -135,14 +135,16 @@ At the center of an Indexer's infrastructure is the Graph Node which monitors Et
 
 - **Ethereum endpoint** - An endpoint that exposes an Ethereum JSON-RPC API. This may take the form of a single Ethereum client or it could be a more complex setup that load balances across multiple. It's important to be aware that certain subgraphs will require particular Ethereum client capabilities such as archive mode and the tracing API.
 
-- **IPFS node (version less than 5)** - Subgraph deployment metadata is stored on the IPFS network. The Graph Node primarily accesses the IPFS node during subgraph deployment to fetch the subgraph manifest and all linked files. Network Indexers do not need to host their own IPFS node, an IPFS node for the network is hosted at https://ipfs.network.thegraph.com.
+- **IPFS node** - Subgraph deployment metadata is stored on the IPFS network. The Graph Node primarily accesses the IPFS node during subgraph deployment to fetch the subgraph manifest and all linked files. Network indexers do not need to host their own IPFS node, an IPFS node for the network is hosted at https://ipfs.network.thegraph.com.
 
 - **Indexer service** - Handles all required external communications with the network. Shares cost models and indexing statuses, passes query requests from gateways on to a Graph Node, and manages the query payments via state channels with the gateway.
 
 - **Indexer agent** - Facilitates the Indexers interactions on chain including registering on the network, managing subgraph deployments to its Graph Node/s, and managing allocations.
 
 - **Prometheus metrics server** - The Graph Node and Indexer components log their metrics to the metrics server.
 
+- **Upcoming: Ethereum Firehose** - a Firehose is a gRPC service providing an ordered, yet fork-aware, stream of blocks, developed by The Graph's core developers to better support performant indexing at scale. This is not currently an indexer requirement, but Indexers are encouraged to familiarise themselves with the technology, ahead of full network support. Learn more about the Firehose [here](https://firehose.streamingfast.io/).
+
 Note: To support agile scaling, it is recommended that query and indexing concerns are separated between different sets of nodes: query nodes and index nodes.
 
 ### Ports overview