Bitcoin Core is the reference implementation of the Bitcoin protocol, serving as both a node to validate transactions and a wallet to store your coins. While it is generally recommended to keep your software up to date, you might need an older version to open a legacy wallet file and access your funds. This article explains where you can find older versions of Bitcoin Core.
Where to find the binaries
Depending on the specific version you require, the files are located on different websites.
Versions 0.8.6 and above
If you need a version of Bitcoin Core from 0.8.6 onwards, you can find the binaries on the official project website. This is the most reliable source for these versions. The download link is https://bitcoincore.org/bin
Pre-release, 0.1.0 and 0.1.3
If you are digging very deep into the past and need the earliest iterations of the software — specifically the pre-release, version 0.1.0 or version 0.1.3 —, these are hosted by the Satoshi Nakamoto Institute: https://satoshi.nakamotoinstitute.org/code
Other versions
Binaries for versions that fall between these two categories are much harder to find, and you often have to settle for sources that are less reliable.
If you have the technical skills, the source code for versions 0.1.5 and above is available on Bitcoin Core’s GitHub repository. However, you will need to compile it by yourself, which is not an easy feat for most users. Here’s the repository URL: https://github.com/bitcoin/bitcoin