OpenVPN Shared Key autogen broken in Jan15 snaps
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Site 2 Site Setups with shared key have a problem with autocreation of shared keys:
Shared Key creation command is throwing an error in the text field 
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If you're interested, I'm available to discuss details of German-speaking paid support (for companies) if needed.
Indeed deprecated:
https://community.openvpn.net/openvpn/wiki/DeprecatedOptions#Option:--secret
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