{
    "mode": "perldoc",
    "parameter": "MongoDB::Upgrading::v1",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3AUpgrading%3A%3Av1/json",
    "generated": "2026-06-14T05:42:51Z",
    "sections": {
        "NAME": {
            "content": "MongoDB::Upgrading::v1 - Deprecations and behavior changes from v0 to v1\n",
            "subsections": []
        },
        "VERSION": {
            "content": "version v2.2.2\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The v1 driver represents a substantial step forward in functionality and consistency. There are\nmany areas where the old API has been deprecated or changed in a backward breaking way.\n\nThis document is intended to help developers update their code to take into account API changes\nfrom the v0 driver to the v1 driver.\n",
            "subsections": []
        },
        "RATIONALE": {
            "content": "Changes to the driver were deemed necessary to achieve certain goals:\n\n*   consistency (intra-driver) – many parts of the v0 API were inconsistent, behaving\ndifferently from method to method; the v1 API minimizes developer surprises by improving\nconsistency in return types and exception mechanisms.\n\n*   consistency (inter-driver) — \"next-generation\" MongoDB drivers across all languages are\nconverging on common APIs and common behaviors; this simplifies developer education and\nsupport, as cross-language examples will be similar.\n\n*   encapsulation – too many low-level, internal operations were exposed as part of the API,\nwhich complicates maintenance work; the v1 API aims to minimize the \"public surface\"\navailable to developers, allowing faster future development keeping up with MongoDB server\nenhancements with less risk of breakage.\n\n*   abstraction – many v0 methods returned raw server documents for end-user code to inspect,\nwhich is brittle in the face of changes in server responses over time; the v1 API uses\nresult classes to abstract the details behind standardized accessors.\n\n*   server compatibility – some new features and behavior changes in the MongoDB server no\nlonger fit the old driver design; the v1 driver transparently supports both old and new\nservers.\n\n*   portability – the v0 driver had a large dependency tree and substantial non-portable C code;\nthe v1 driver removes some dependencies and uses widely-used, well-tested CPAN modules in\nplace of custom C code where possible; it lays the groundwork for a future \"pure-Perl\noptional\" driver.\n\n*   round-trippable data – the v0 BSON implementation could easily change data types when\nround-tripping documents; the v1 driver is designed to round-trip data correctly whenever\npossible (within the limits of Perl's dynamic typing).\n",
            "subsections": []
        },
        "INSTALLATION AND DEPENDENCY CHANGES": {
            "content": "",
            "subsections": [
                {
                    "name": "Moo instead of Moose",
                    "content": "The v1 driver uses Moo instead of Moose. This change results in a slightly faster driver and a\nsignificantly reduced deep dependency tree.\n\nSSL and SASL\nThe v0 driver required a compiler and OpenSSL and libgsasl for SSL and SASL support,\nrespectively. The v1 driver instead relies on CPAN modules \"IO::Socket::SSL\" and \"Authen::SASL\"\nfor SSL and SASL support, respectively.\n\nSSL configuration is now possible via the ssl attribute.\n\nAuthentication configuration is described in \"AUTHENTICATION\" in MongoDB::MongoClient.\n"
                }
            ]
        },
        "BEHAVIOR CHANGES": {
            "content": "",
            "subsections": [
                {
                    "name": "MongoClient configuration",
                    "content": "New configuration options\nSeveral configuration options have been added, with particular emphasis on adding more granular\ncontrol of timings and timeout behaviors.\n\n*   \"authmechanism\"\n\n*   \"authmechanismproperties\"\n\n*   \"bsoncodec\"\n\n*   \"connecttimeoutms\"\n\n*   \"heartbeatfrequencyms\"\n\n*   \"localthresholdms\"\n\n*   \"maxtimems\"\n\n*   \"replicasetname\"\n\n*   \"readprefmode\"\n\n*   \"readpreftagsets\"\n\n*   \"serverselectiontimeoutms\"\n\n*   \"socketcheckintervalms\"\n\n*   \"sockettimeoutms\"\n\nReplica set configuration\nConnecting to a replica set now requires a replica set name, given either with the\n\"replicasetname\" option for MongoDB::MongoClient or with the \"replicaSet\" option in a\nconnection string. For example:\n\n$client = MongoDB::MongoClient->new(\nhost => \"mongodb://rs1.example.com,rs2.example.com/\",\nreplicasetname => 'theset',\n);\n\n$client = MongoDB::MongoClient->new(\nhost => \"mongodb://rs1.example.com,rs2.example.com/?replicaSet=theset\"\n);\n\nConfiguration options changed to read-only\nConfiguration options are changing to be immutable to prevent surprising action-at-a-distance.\n(E.g. changing an attribute value in some part of the code changes it for other parts of the\ncode that didn't expect it.) Going forward, options may be set at MongoDB::MongoClient\nconstruction time only.\n\nThe following options have changed to be read-only:\n\n*   \"dbname\"\n\n*   \"j\"\n\n*   \"password\"\n\n*   \"ssl\"\n\n*   \"username\"\n\n*   \"w\"\n\n*   \"wtimeout\"\n\nWrite concern may be overridden at the MongoDB::Database and MongoDB::Collection level during\nconstruction of those objects. For more details, see the later section on write concern changes.\n\nMapping between connection string and configuration options\nMany configuration options may be set via a connection string URI in the \"host\" option. In the\nv0 driver, the precedence between the connection string and constructor options was completely\ninconsistent. In the v1 driver, options set via a connection string URI will take precedence\nover options passed to the constructor. This is consistent with with other MongoDB drivers (as\nwell as how DBI treats Data Source Names).\n\nThe list of servers and ports as well as the optional \"username\", \"password\" and \"dbname\"\noptions come directly from URI structure. Other options are parsed as key-value parameters at\nthe end of the connection string. The following table shows how connection string keys map to\nconfiguration options in the MongoDB::MongoClient:\n\nConnection String Key           MongoClient option\n---------------------------     -----------------------------\nauthMechanism                   authmechanism\nauthMechanismProperties         authmechanismproperties\nconnectTimeoutMS                connecttimeoutms\nheartbeatFrequencyMS            heartbeatfrequencyms\njournal                         j\nlocalThresholdMS                localthresholdms\nmaxTimeMS                       maxtimems\nreadPreference                  readprefmode\nreadPreferenceTags              readpreftagsets\nreplicaSet                      replicasetname\nserverSelectionTimeoutMS        serverselectiontimeoutms\nsocketCheckIntervalMS           socketcheckintervalms\nsocketTimeoutMS                 sockettimeoutms\nssl                             ssl\nw                               w\nwTimeoutMS                      wtimeout\n\nThe \"readPreferenceTags\" and \"authMechanismProperties\" keys take colon-delimited,\ncomma-separated pairs:\n\nreadPreferenceTags=dc:nyeast,rack:1\nauthMechanismProperties=SERVICENAME:mongodb\n\nThe \"readPreferenceTags\" option may be repeated to build up a list of tag set documents:\n\nreadPreferenceTags=dc:nyc,rack:1&readPreferenceTags=dc:nyc\n\nDeprecated configuration options\nSeveral options have been superseded, replaced or renamed for clarity and are thus deprecated\nand undocumented. They are kept for a limited degree of backwards compatibility. They will be\ngenerally be used as fallbacks for other options. If any were read-write, they have also been\nchanged to read-only.\n\n*   \"dttype\" — see \"BSON encoding changes\" for details.\n\n*   \"querytimeout\" — replaced by \"sockettimeoutms\"; if set, this will be used as a fallback\ndefault for \"sockettimeoutms\".\n\n*   \"sasl\" — superseded by \"authmechanism\"; if set, this will be used along with\n\"saslmechanism\" as a fallback default for \"authmechanism\".\n\n*   \"saslmechanism\" — superseded by \"authmechanism\"; if set, this will be used as a fallback\ndefault for \"authmechanism\".\n\n*   \"timeout\" — replaced by \"connecttimeoutms\"; if set, this will be used as a fallback\ndefault for \"connecttimeoutms\".\n\nThese will be removed in a future major release.\n\nConfiguration options removed\nSome configuration options have been removed entirely, as they no longer serve any purpose given\nchanges to server discovery, server selection and connection handling:\n\n*   \"autoconnect\"\n\n*   \"autoreconnect\"\n\n*   \"findmaster\"\n\n*   \"maxbsonsize\"\n\nAs described further below in the \"BSON encoding changes\" section, these BSON encoding\nconfiguration options have been removed as well:\n\n*   \"inflatedbrefs\"\n\n*   \"inflateregexps\"\n\nRemoved configuration options will be ignored if passed to the MongoDB::MongoClient constructor.\n"
                },
                {
                    "name": "Lazy connections and reconnections on demand",
                    "content": "The improved approach to server monitoring and selection allows all connections to be lazy. When\nthe client is constructed, no connections are made until the first network operation is needed.\nAt that time, the client will scan all servers in the seed list and begin regular monitoring.\nConnections that drop will be re-established when needed.\n\nIMPORTANT: Code that used to rely on a fatal exception from \"MongoDB::MongoClient->new\" when no\nmongod is available will break. Instead, users are advised to just conduct their operations and\nbe prepared to handle errors.\n\nFor testing, users may wish to run a simple command to check that a mongod is ready:\n\nuse Test::More;\n\n# OLD WAY: BROKEN\nplan skipall => 'no mongod' unless eval {\nMongoDB::MongoClient->new\n};\n\n# NEW WAY 1: with MongoDB::MongoClient\nplan skipall => 'no mongod' unless eval {\nMongoDB::MongoClient->new->db('admin')->runcommand(\n[ ismaster => 1 ]\n)\n};\n\n# NEW WAY 2: with MongoDB and connect\nplan skipall => 'no mongod' unless eval {\nMongoDB->connect->db('admin')->runcommand([ ismaster => 1 ])\n};\n\nSee SERVER SELECTION and SERVER MONITORING AND FAILOVER in MongoDB::MongoClient for details.\n"
                },
                {
                    "name": "Exceptions are the preferred error handling approach",
                    "content": "In the v0 driver, errors could be indicated in various ways:\n\n*   boolean return value\n\n*   string return value is an error; hash ref is success\n\n*   document that might contain an 'err', 'errmsg' or '$err' field\n\n*   thrown string exception\n\nRegardless of the documented error handling, every method that involved a network operation\nwould throw an exception on various network errors.\n\nIn the v1 driver, exceptions objects are the standard way of indicating errors. The exception\nhierarchy is described in MongoDB::Error.\n"
                },
                {
                    "name": "Cursors and query responses",
                    "content": "In v0, MongoDB::Cursor objects were used for ordinary queries as well as the query-like commands\naggregation and parallel scan. However, only cursor iteration commands worked for aggregation\nand parallel scan \"cursors\"; the rest of the MongoDB::Cursor API didn't apply and was fatal.\n\nIn v1, all result iteration is done via the new MongoDB::QueryResult class. MongoDB::Cursor is\nnow just a thin wrapper that holds query parameters, instantiates a MongoDB::QueryResult on\ndemand, and passes iteration methods through to the query result object.\n\nThis significantly simplifies the code base and should have little end-user visibility unless\nusers are specifically checking the return type of queries and query-like methods.\n\nThe \"explain\" cursor method no longer resets the cursor.\n\nThe \"slaveokay\" cursor method now sets the \"readpreference\" to 'secondaryPreferred' or clears\nit to 'primary'.\n\nThe \"snapshot\" cursor method now requires a boolean argument, allowing it to be turned on or off\nbefore executing the query. Calling it without an argument (as it was in v0) is a fatal\nexception.\n\nParallel scan \"cursors\" are now QueryResult objects, with the same iteration methods as in v0.\n\nThe $MongoDB::Cursor::slaveokay global variable has been removed as part of the revision to\nread preference handling. See the read preferences section below for more details.\n\nThe $MongoDB::Cursor::timeout global variable has also been removed. Timeouts are set during\nMongoDB::MongoClient configuration and are immutable. See the section on configuration changes\nfor more.\n"
                },
                {
                    "name": "Aggregation API",
                    "content": "On MongoDB 2.6 or later, \"aggregate\" always uses a cursor to execute the query. The \"batchSize\"\noption has been added (but has no effect prior to 2.6). The \"cursor\" option is deprecated.\n\nThe return types for the \"aggregate\" method are now always QueryResult objects, regardless of\nwhether the aggregation uses a cursor internally or is an 'explain'.\n\nNOTE: To help users with a 2.6 mongos and mixed version shards with versions before 2.6, passing\nthe deprecated 'cursor' option with a false value will disable the use of a cursor. This\nworkaround is provided for convenience and will be removed when 2.4 is no longer supported.\n"
                },
                {
                    "name": "Read preference objects and the readpreference method",
                    "content": "A new MongoDB::ReadPreference class is used to encapsulate read preference attributes. In the v1\ndriver, it is constructed from the \"readprefmode\" and \"readpreftagsets\" attributes on\nMongoDB::MongoClient:\n\nMongoDB::MongoClient->new(\nreadprefmode => 'primaryPreferred',\nreadpreftagsets => [ { dc => 'useast' }, {} ],\n);\n\nThe old \"readpreference\" method to change the read preference has been removed and trying to\nset a read preference after the client has been created is a fatal error. The old mode constants\nPRIMARY, SECONDARY, etc. have been removed.\n\nThe \"readpreference\" method now returns the MongoDB::ReadPreference object generated from\n\"readprefmode\" and \"readpreftagsets\".\n\nIt is inherited by MongoDB::Database, MongoDB::Collection, and MongoDB::GridFS objects unless\nprovided as an option to the relevant factory methods:\n\nmy $coll = $db->getcollection(\n\"foo\", { readpreference => 'secondary' }\n);\n\nSuch \"readpreference\" arguments may be a MongoDB::ReadPreference object, a hash reference of\narguments to construct one, or a string that represents the read preference mode.\n\nMongoDB::Database and MongoDB::Collection also have \"clone\" methods that allow easy alteration\nof a read preference for a limited scope.\n\nmy $coll2 = $coll->clone( readpreference => 'secondaryPreferred' );\n\nFor MongoDB::Cursor, the \"readpreference\" method sets a hidden read preference attribute that\nis used for the query in place of the MongoDB::MongoClient default \"readpreference\" attribute.\nThis means that calling \"readpreference\" on a cursor object no longer changes the read\npreference globally on the client – the read preference change is scoped to the cursor object\nonly.\n"
                },
                {
                    "name": "Write concern objects and removing the safe argument",
                    "content": "A new MongoDB::WriteConcern class is used to encapsulate write concern attributes. In the v1\ndriver, it is constructed from the \"w\", \"wtimeout\" and \"j\" attributes on MongoDB::MongoClient:\n\nMongoDB::MongoClient->new( w => 'majority', wtimeout => 1000 );\n\nThe \"writeconcern\" method now returns the MongoDB::WriteConcern object generated from \"w\",\n\"wtimeout\" and \"j\".\n\nIt is inherited by MongoDB::Database, MongoDB::Collection, and MongoDB::GridFS objects unless\nprovided as an option to the relevant factory methods:\n\n$db = $client->getdatabase(\n\"test\", { writeconcern => { w => 'majority' } }\n);\n\nSuch \"writeconcern\" arguments may be a MongoDB::WriteConcern object, a hash reference of\narguments to construct one, or a string that represents the \"w\" mode.\n\nMongoDB::Database and MongoDB::Collection also have \"clone\" methods that allow easy alteration\nof a write concern for a limited scope.\n\nmy $coll2 = $coll->clone( writeconcern => { w => 1 } );\n\nThe \"safe\" argument is no longer used in the new CRUD API.\n"
                },
                {
                    "name": "Authentication based only on configuration options",
                    "content": "Authentication now happens automatically on connection during the \"handshake\" with any given\nserver based on the authmechanism attribute.\n\nThe old \"authenticate\" method in MongoDB::MongoClient has been removed.\n"
                },
                {
                    "name": "Bulk API",
                    "content": "Bulk method names changed to match CRUD API\nMethod names match the new CRUD API, e.g. \"insertone\" instead of \"insert\" and so one. The\nlegacy names are deprecated.\n\nBulk insertion\nInsertion via the bulk API will NOT insert an \"id\" into the original document if one does not\nexist. Previous documentation was not specific whether this was the case or if the \"id\" was\nadded to the document sent to the server.\n\nBulk write results\nThe bulk write results class has been renamed to MongoDB::BulkWriteResult. It keeps\n\"MongoDB::WriteResult\" as an empty superclass for some backwards compatibility so that\n\"$result->isa(\"MongoDB::WriteResult\")\" will continue to work as expected.\n\nThe attributes have been renamed to be consistent with the new CRUD API. The legacy names are\ndeprecated, but are available as aliases.\n"
                },
                {
                    "name": "GridFS",
                    "content": "The MongoDB::GridFS class now has explicit read preference and write concern attributes\ninherited from MongoDB::MongoClient or MongoDB::Database, just like MongoDB::Collection. This\nmeans that GridFS operations now default to an acknowledged write concern, just like collection\noperations have been doing since v0.502.0 in 2012.\n\nThe use of \"safe\" is deprecated.\n\nSupport for ancient, undocumented positional parameters circa 2010 has been removed.\n"
                },
                {
                    "name": "Low-level functions removed",
                    "content": "Low-level driver functions have been removed from the public API.\n"
                },
                {
                    "name": "MongoDB::Connection removed",
                    "content": "The \"MongoDB::Connection\" module was deprecated in v0.502.0 and has been removed.\n\nBSON encoding changes\nIn the v1 driver, BSON encoding and decoding have been encapsulated into a MongoDB::BSON codec\nobject. This can be provided at any level, from MongoDB::MongoClient to MongoDB::Collection. If\nnot provided, a default will be created that behaves similarly to the v0 encoding/decoding\nfunctions, except for the following changes.\n\n$MongoDB::BSON::usebinary removed\nHistorically, this defaulted to false, which corrupts binary data when round tripping.\nRetrieving a binary data element and re-inserting it would have resulted in a field with UTF-8\nencoded string of binary data.\n\nGoing forward, binary data will be returned as a MongoDB::BSON::Binary object. A future driver\nmay add the ability to control decoding to allow alternative representations.\n\n$MongoDB::BSON::useboolean removed\nThis global variable never worked. BSON booleans were always deserialized as boolean objects. A\nfuture driver may add the ability to control boolean representation.\n\n$MongoDB::BSON::utf8flagon removed\nIn order to ensure round-tripping of string data, this variable is removed. BSON strings will\nalways be decoded to Perl character strings. Anything else risks double-encoding a round-trip.\n\n$MongoDB::BSON::lookslikenumber and $MongoDB::BSON::char\ndeprecated and re-scoped\nIn order to allow a future driver to provide more flexible user-customized encoding and\ndecoding, these global variables are deprecated. If set, they will be examined during\n\"MongoDB::MongoClient->new()\" to set the configuration of a default MongoDB::BSON codec (if one\nis not provided). Changing them later will NOT change the behavior of the codec object.\n\n\"MongoDB::MongoClient\" option \"inflateregexps\" removed\nPreviously, BSON regular expressions decoded to \"qr{}\" references by default and the\n\"MongoDB::MongoClient\" \"inflateregexps\" option was available to decode instead to\nMongoDB::BSON::Regexps.\n\nGoing forward in the v1.0.0 driver, for safety and consistency with other drivers, BSON regular\nexpressions always decode to MongoDB::BSON::Regexp objects.\n\n\"MongoDB::MongoClient\" option \"inflatedbrefs\" removed\nThe \"inflatedbrefs\" configuration option has been removed and replaced with a \"dbrefcallback\"\noption in MongoDB::BSON.\n\nBy default, the \"MongoDB::MongoClient\" will create a MongoDB::BSON codec that will construct\nMongoDB::DBRef objects. This ensures that DBRefs properly round-trip.\n\n\"MongoDB::MongoClient\" option \"dttype\" deprecated and changed to read-only\nThe \"dttype\" option is now only takes effect if \"MongoDB::MongoClient\" constructs a\nMongoDB::BSON codec object. It has been changed to a read-only attribute so that any code that\nrelied on changing \"dttype\" after constructing a \"MongoDB::MongoClient\" object will fail\ninstead of being silently ignored.\n\nInt32 vs Int64 encoding changes\nOn 64-bit Perls, integers that fit in 32-bits will be encoded as BSON Int32 (whereas previously\nthese were always encoded as BSON Int64).\n\nMath::BigInt objects will always be encoded as BSON Int64, which allows users to force 64-bit\nencoding if desired.\n\nAdded support for Time::Moment\nTime::Moment is a much faster replacement for the venerable DateTime module. The BSON codec will\nserialize Time::Moment objects correctly and can use that module as an argument for the\n\"dttype\" codec attribute.\n\nAdded support for encoding common JSON boolean classes\nMost JSON libraries on CPAN implement their own boolean classes. The following libraries boolean\ntypes will now encode correctly as BSON booleans:\n\n*   JSON::XS\n\n*   Cpanel::JSON::XS\n\n*   JSON::PP\n\n*   JSON::Tiny\n\n*   Mojo::JSON\n\nDBRef objects\nThe \"fetch\" method and related attributes \"client\", \"verifydb\", and \"verifycoll\" have been\nremoved from MongoDB::DBRef.\n\nProviding a \"fetch\" method was inconsistent with other MongoDB drivers, which either never\nprovided it, or have dropped it in the next-generation drivers. It requires a \"client\"\nattribute, which tightly couples BSON decoding to the client model, causing circular reference\nissues and triggering Perl memory bugs under threads. Therefore, the v1.0.0 driver no longer\nsupport fetching directly from MongoDB::DBRef; users will need to implement their own methods\nfor dereferencing.\n\nAdditionally, the \"db\" attribute is now optional, consistent with the specification for DBRefs.\n\nAlso, all attributes (\"ref\", \"id\" and \"db\") are now read-only, consistent with the move toward\nimmutable objects throughout the driver.\n\nTo support round-tripping DBRefs with additional fields other than $ref, $id and $db, the DBRef\nclass now has an attribute called \"extra\". As not all drivers support this feature, using it for\nnew DBRefs is not recommended.\n"
                }
            ]
        },
        "DEPRECATED METHODS": {
            "content": "Deprecated options and methods may be removed in a future release. Their documentation has been\nremoved to discourage ongoing use. Unless otherwise stated, they will continue to behave as they\npreviously did, allowing a degree of backwards compatibility until code is updated to the new\nMongoDB driver API.\n",
            "subsections": [
                {
                    "name": "MongoDB::Database",
                    "content": "*   eval – MongoDB 3.0 deprecated the '$eval' command, so this helper method is deprecated as\nwell.\n\n*   lasterror — Errors are now indicated via exceptions at the time database commands are\nexecuted.\n"
                },
                {
                    "name": "MongoDB::Collection",
                    "content": "*   insert, batchinsert, remove, update, save, query and findandmodify — A new common driver\nCRUD API replaces these legacy methods.\n\n*   getcollection — This method implied that collections could be contained inside collection.\nThis doesn't actually happen so it's confusing to have a Collection be a factory for\ncollections. Users who want nested namespaces should be explicit and create them off\nDatabase objects instead.\n\n*   ensureindex, dropindexes, dropindex, getindex — A new MongoDB::IndexView class is\naccessible through the \"indexes\" method, offering greater consistency in behavior across\ndrivers.\n\n*   validate — The return values have changed over different server versions, so this method is\nrisky to use; it has more use as a one-off tool, which can be accomplished via\n\"runcommand\".\n"
                },
                {
                    "name": "MongoDB::CommandResult",
                    "content": "*   result — has been renamed to 'output' for clarity\n"
                },
                {
                    "name": "MongoDB::Cursor",
                    "content": "*   slaveok — this modifier method is superseded by the 'readpreference' modifier method\n\n*   count — this is superseded by the \"MongoDB::Collection#count\" in MongoDB::Collection count\nmethod. Previously, this ignored skip/limit unless a true argument was passed, which was a\nbizarre, non-intuitive and inconsistent API.\n"
                },
                {
                    "name": "MongoDB::BulkWrite and MongoDB::BulkWriteView",
                    "content": "*   insert — renamed to 'insertone' for consistency with CRUD API\n\n*   update — renamed to 'updatemany' for consistency with CRUD API\n\n*   remove — renamed to 'deletemany' for consistency with CRUD API\n\n*   removeone — renamed to 'deleteone' for consistency with CRUD API\n"
                }
            ]
        },
        "AUTHORS": {
            "content": "*   David Golden <david@mongodb.com>\n\n*   Rassi <rassi@mongodb.com>\n\n*   Mike Friedman <friedo@friedo.com>\n\n*   Kristina Chodorow <k.chodorow@gmail.com>\n\n*   Florian Ragwitz <rafl@debian.org>\n",
            "subsections": []
        },
        "COPYRIGHT AND LICENSE": {
            "content": "This software is Copyright (c) 2020 by MongoDB, Inc.\n\nThis is free software, licensed under:\n\nThe Apache License, Version 2.0, January 2004\n",
            "subsections": []
        }
    },
    "summary": "MongoDB::Upgrading::v1 - Deprecations and behavior changes from v0 to v1",
    "flags": [],
    "examples": [],
    "see_also": []
}