Versions: R5; ND6; ND6.5; ND7; ND8; ND8.5
Tweet Tweet: 'Max length of environment variable value: 251 characters'
251 characters, possibly up to 253
As pointed out in a comment, while this is technically 255 for the whole string, that has to include at least a one character variable name and the equals sign, and possibly the CRLF characters at the end. Probably no more than 251, possibly 253, in practice.
Comments about limit:
Probably including variable name & = sign and possibly the CR/LF line termination, so in practice value limit is lower.
Excellent point, Tim. I have updated the comment to reflect that.
Tired of limits?
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We don't stop at the Limits of Lotus Notes/Domino... we start there.