Shouldn't it also have a "How to upgrade" for Linux OS?? I don't know why only Windows users are worth of the "How to".... 
Miss this part?
or just copy over /Applications/Bitcoin-Qt (on macOS)
or bitcoind/bitcoin-qt (on Linux).
or bitcoind/bitcoin-qt (on Linux).
I think many linux users also use package managers which will handle this automatically.
Is that enough to hanle all binaries? Only by copying bitcoind? What about bicoin-cli and all other binaires?
I was expecting to see some instructions for installing from scratch. Like cloning repository, or at least downloading source code, installing dependencies, and minimal commands to compile, make and install binaries!
What I see in the docs (./docs/INSTALL.md) is mostly for Ubuntu specific distro.
I cannot find either any reference to any package related to bitcoin in my Debian package manager
Code:
psysc0rpi0n@rockpro64:~$ apt-cache search bitcoind
psysc0rpi0n@rockpro64:~$ apt-cache search bitcoin
bruteforce-wallet - try to find the password of an encrypted wallet file
python3-btchip - Python library to communicate with BTChip dongle (Python 3)
electrum - Easy to use Bitcoin client
python3-electrum - Easy to use Bitcoin client - Python module
golang-github-btcsuite-btcd-btcec-dev - Go library for Elliptic curve cryptography
libbase58-0 - library for Bitcoin's base58 encoding
libbase58-dev - library for Bitcoin's base58 encoding -- development files
libencode-base58-perl - module to shorten numbers using a base58 conversion
libsecp256k1-0 - library for EC operations on curve secp256k1
libsecp256k1-dev - library for EC operations on curve secp256k1 - development headers
litecoin-qt - peer-to-peer network based digital currency - Qt GUI
litecoind - peer-to-peer network based digital currency - daemon
base58 - base58 encode/decode: command-line interface
python3-base58 - base58 encode/decode for Python
python3-bip32utils - Python implementation of Bitcoin hierarchical deterministic wallet
python3-bitcoinlib - Python module with an easy interface to the Bitcoin protocol
python3-mnemonic - Implementation of Bitcoin BIP-0039 (Python 3)
python3-stdnum - Python module to handle standardized numbers and codes (Python3 version)
python3-trezor - library for communicating with TREZOR Bitcoin HW wallet (Python 3)
trezor - utilities for communicating with TREZOR Bitcoin HW wallet
psysc0rpi0n@rockpro64:~$
psysc0rpi0n@rockpro64:~$ apt-cache search bitcoin
bruteforce-wallet - try to find the password of an encrypted wallet file
python3-btchip - Python library to communicate with BTChip dongle (Python 3)
electrum - Easy to use Bitcoin client
python3-electrum - Easy to use Bitcoin client - Python module
golang-github-btcsuite-btcd-btcec-dev - Go library for Elliptic curve cryptography
libbase58-0 - library for Bitcoin's base58 encoding
libbase58-dev - library for Bitcoin's base58 encoding -- development files
libencode-base58-perl - module to shorten numbers using a base58 conversion
libsecp256k1-0 - library for EC operations on curve secp256k1
libsecp256k1-dev - library for EC operations on curve secp256k1 - development headers
litecoin-qt - peer-to-peer network based digital currency - Qt GUI
litecoind - peer-to-peer network based digital currency - daemon
base58 - base58 encode/decode: command-line interface
python3-base58 - base58 encode/decode for Python
python3-bip32utils - Python implementation of Bitcoin hierarchical deterministic wallet
python3-bitcoinlib - Python module with an easy interface to the Bitcoin protocol
python3-mnemonic - Implementation of Bitcoin BIP-0039 (Python 3)
python3-stdnum - Python module to handle standardized numbers and codes (Python3 version)
python3-trezor - library for communicating with TREZOR Bitcoin HW wallet (Python 3)
trezor - utilities for communicating with TREZOR Bitcoin HW wallet
psysc0rpi0n@rockpro64:~$