1. Fixed POS transition (including Panda banner) broken in the previous release.
2. Fixed panics during header downloader, introduced in the previous release.
3. Reduced network traffic consumption by the header downloader. Eliminated another cause for stuck header download.
4. Allowed block snapshots for bor (mumbai testnet and mainnet), but not enabled by default yet. NOTE: Looks like bor mainnet is not working yet (i.e. state root hash does not match - investigation in progress).
5. Further reduction of the memory footprint of using block snapshots (more compact Huffman decoding tables).